Step heating method and heating system for preheating of gas fractionating tower inlet material

Abstract

The invention relates to a step heating method and heating system for preheating of a gas fractionating tower inlet material. The heating method includes: preheating a material by a hot water / material heat exchanger outside a fractionating tower to 80+ / -10DEG C, letting the preheated material enter the fractionating tower, heating the material by a bottom reboiler in the tower and maintaining a working temperature required by material fractionation to realize step heating of the material. The heating system comprises a petroleum fractionating heating system component and a waste heat recovery inlet material heating system component. Specifically, the gas fractionating heating system component comprises: the fractionating tower, an air cooler, a water cooled heat exchanger and the reboiler; and the waste heat recovery inlet material heating system component includes: the hot water / material heat exchanger and a steam type lithium bromide absorption type heat pump. The method and the system provided by the invention utilize the recovered waste heat to preheat the inlet material, realize energy step utilization of the fractionating tower heating process, reduce the process steam consumption by over 20%, improve the energy utilization rate, and save the cost.

Description

technical field [0001] The invention belongs to the field of petroleum refining and chemical production, and relates to a cascaded heating method and heating system for preheating the inlet materials of a gas fractionation tower, and in particular to the recovery of waste heat from the top product material of the gas fractionation tower and the combined waste heat of other process heat in petroleum refining. A method and system for cascaded heating of inlet materials of a fractionation tower. Background technique [0002] With the rapid development of the national economy, the social demand for petrochemical products is increasing, and the energy consumption of this industry accounts for more than 10% of the total energy consumption in the country. In the production of petroleum refineries, the process of gas fractionation is a large heat consumer. The process flow of the conventional gas fractionation process is as follows: figure 1 As shown, it mainly includes the followi...

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Problems solved by technology

[0003] Disadvantage 1 is: the waste heat of the product hot material (oil and gas) at the top outlet of the fractionation tower is lost to the environment through the air cooler, water-cooled heat exchanger and its circulating water system, resulting in a large amount of energy waste

[0004] Disadvantage 2 is: the normal temperature (about 20°C) inlet material of the fractionation tower is heated by the bottom reboiler and maintained to the working temperature, and the working temperature of the bottom material of the alcohol amine regeneration, depropanization, catalytic distillation and other processes is about 110 ℃, the reboiler usually uses process steam with a pressure of about 0.3MPa as the heating medium. This heating mode has a large heat transfer temperature difference, a large increase in entropy in the heating process, and unreasonable use of energy.

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