Abstract: A large integrated refining and chemical enterprise extends its industrial chain by using the self-produced n-butane raw material and adopting the n-butane oxidation to produce maleic anhydride (maleic anhydride) process route to produce BDO (1,4-butanediol). In order to improve its competitive advantage with the alkyne aldehyde process, further reduce the operating cost of the device, and tap the potential for energy saving and consumption reduction of the device, a low-grade hot water preheating scheme is proposed to save 25.35 t/h of steam consumption in the rear heater. A n-butane staged vaporization scheme is also proposed to reuse the hot water from the isobutane refining unit's deisobutane tower reboiler, saving 4.07 t/h of n-butane vaporization steam consumption. A deep coupling scheme for oxidation incineration is proposed, which uses the waste heat of the incineration system to preheat boiler feedwater and superheated high-pressure steam separately, increasing high-pressure steam production by 13.8%. The comprehensive energy consumption has been reduced to -900.55 kgCE/t (maleic anhydride,1 kgCE = 29.3 MJ)), achieving good economic benefits. At the same time, the acid hydrolysis oxidation wastewater treatment process has been proposed, and it is estimated that the comprehensive energy consumption per unit product can be reduced by 55.3 kgCE/t (maleic anhydride), while reducing the difficulty of treating high chemical oxygen demand wastewater and promoting the green transformation of degradable materials.

Key words: maleic anhydride, n-butane, oxidation, preheated air, graded vaporization, wastewater, chemical oxygen demand