Novel heat energy utilization system and novel heat energy utilization method for cyclohexanol production

Abstract

The invention discloses a novel heat energy utilization system and a novel heat energy utilization method for cyclohexanol production. The novel heat energy utilization system comprises a benzene recovery tower heat energy utilization unit, a cyclohexene recovery tower heat energy utilization unit, a cyclohexene removal tower heat energy utilization unit and a cyclohexane refining tower heat energy utilization unit. The novel heat energy utilization system and the novel heat energy utilization method for cyclohexanol production have the advantages that the process heat in the system can be utilized and recovered to the maximum limit, the consumption of boiler steam is reduced, simultaneously the usage amount of industrial circulating water is reduced, and the consumption of circulating water and the consumption of electric energy are reduced. The novel heat energy utilization system for cyclohexanol production has the characteristics that according to the level of the energy of each device for cyclohexanol production, reasonable heat recovery ways and heat exchange devices are designed, and energy saving and consumption reduction are realized to the maximum limit. By adopting the processes and the devices disclosed by the invention, the consumption of the steam for per ton of cyclohexanol can be reduced by 2.0-2.5 tons, the usage amount of the circulating water can be reduced by 200-250 tons, and the production cost can be reduced by 350-425 yuan / ton.

Description

technical field [0001] The invention relates to the technical field of cyclohexanol production, in particular to a new thermal energy utilization system and thermal energy utilization method in cyclohexanol production. Background technique [0002] The production of cyclohexanol generally starts with selective hydrogenation of benzene to obtain a mixture of benzene, cyclohexene and cyclohexane, which undergoes extraction and rectification in four towers to obtain cyclohexene, and then undergoes hydration reaction of cyclohexene to obtain cyclohexene Alcohol; a series of equipment is required in the whole process, such as benzene separation tower, benzene recovery tower, etc. are required in the benzene separation and recovery process; cyclohexene separation tower, cyclohexene recovery tower, etc. are required in the cyclohexene separation and recovery process; The refining process of cyclohexane requires a cyclohexane refining tower, a cyclohexane refining tower gas phase co...

AI Technical Summary

Problems solved by technology

[0002] The production of cyclohexanol generally starts with selective hydrogenation of benzene to obtain a mixture of benzene, cyclohexene and cyclohexane, which undergoes extraction and rectification in four towers to obtain cyclohexene, and then undergoes hydration reaction of cyclohexene to obtain cyclohexene Alcohol; a series of equipment is required in the whole process, such as benzene separation tower, benzene recovery tower, etc. are required in the benzene separation and recovery process; cyclohexene separation tower, cyclohexene recovery tower, etc. are required in the cyclohexene separation and recovery process; The refining process of cyclohexane requires a cyclohexane refining tower, a cyclohexane refining tower gas phase condenser, etc.; the refining process of cyclohexanol requires a cyclohexanol separation tower, a decyclohexene tower, etc. In the unit material heating and cooling device, there are many unreasonable heat utilization problems, resulting in low heat utilization rate, heat waste, and high energy consumption. At present, the heat required by each equipment in the entire production of cyclohexanol is provided by Provided by external steam, most of the process waste heat in each link is cooled by industrial circulating water, which has not realized the efficient recycling of heat in each link, resulting in waste of heat and high production costs. Specifically:

[0003] 1. The DMAC still liquid at about 150°C in the benzene recovery tower is the most advanced at present. It is pumped out by its still pump to heat the still liquid at about 80°C in the cyclohexanol separation tower, and then to heat the feed to the benzene separation tower. The temperature is still low. The relatively high DMAC is cooled by circulating water and then enters the benzene separation tower to circulate and absorb benzene. The heat utilization rate of the whole process is very low; 2. The DMAC kettle liquid of the cyclohexene recovery tower at about 150 ° C is currently the most advanced. The pump is pumped out to the cyclohexanol separation tower at about 80°C for heating, and then to heat the material cyclohexene entering the hydration reactor. The DMAC, which is still at a relatively high temperature, is cooled by circulating water and then enters the cyclohexene separation tower for circulation. Absorbing cyclohexene, the heat utilization rate of the whole process is also relatively low; 3. The cyclohexanol gas at about 155 °C produced from the side line of the decyclohexene tower is directly fed to the cyclohexanol reactor with a lower temperature. After heating and condensing with circulating water, the cyclohexanol pump is used to preheat the cyclohexene feed to the cyclohexanol reactor, and then cooled by circulating water and sent to the cyclohexanol intermediate product storage tank. The heat utilization rate of the whole process is Lower; 4. The cyclohexane vapor at about 90°C at the top outlet of the cyclohexane refining tower is directly sent to the gas phase condenser of the cyclohexane refining tower for condensation with circulating water, resulting in a waste of high-grade heat energy; 5. Cyclohexane The still liquid of the refining tower needs to be kept at 85-110°C, the still liquid of the cyclohexanol separation tower needs to be kept at about 80°C, and the feed cyclohexene of the cyclohexanol reactor also needs to be continuously heated by external steam

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