| According to the actual situation of the domestic synthetic ammonia production and the actual production status of 250000 tons/year synthetic ammonia production process in author's unit, the problems and optimizable methods for two energy-saving kinds of Benfield decarbonization process were summarized in this article. Two kinds of process includes twin towers pressure regeneration- two-stage absorption process and single tower two-stage regeneration-two-stage absorption process. It is indicated that large amounts of low level heat exist in Benfield decarbonization process. This paper mainly focused on how to make full use of the low level heat, such as the low temperature waste heat and the barren solution waste heat.The main contents are as follows. First, the hot water type lithium bromide unit which capacity is 2290kW was driven by the barren solution waste heat in Benfield decarbonization process Hence,7? 394 t/h low temperature cold water are available under the original production process. Second, waste heat boiler in decarbonization process produced about 9 tons of 0.3MPa low pressure steam. Use of the steam,700 t/h low temperature cold water of 10? difference and outlet temperature 8? were obtained through driving two sets of 8140kW refrigerating capacity steam type lithium bromide units.Low temperature cold water produced by two sets of lithium bromide units can be used as cool medium in synthetic ammonia system. On the one hand, a lot of circulating water used to cool will be saved in synthetic ammonia process. On the other hand, the increase of synthetic ammonia reaches 35t/d.The Benfield decarbonization system optimization of lithium bromide units and the industrial application example presented in this paper is the first case in the domestic synthetic ammonia production process. It is remarkable for energy saving. Therefore, the optimization method has good popularization and application value in the industry. |
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