(1) Technical scope of application

Used in chemical and other industries, a process that uses idle heat exchangers and steam condensate to preheat the inlet water of the steam drum.

(2) Technical principles (transformation content)

① Technical introduction

The HCN reaction is an exothermic reaction that uses boiler water to remove the heat generated by the reaction and passes through a steam drum to produce 10barg of steam. The higher the HCN production, the more steam produced, and the higher the temperature of the boiler water entering the reaction system, the more 10Barg steam can be produced.

② Energy saving principles

The 10barg steam condensate from the downstream device exchanges heat with the inlet water of the steam drum through the heat exchanger. The inlet water temperature of the boiler water of the steam drum increases from 105℃ to 145℃, which greatly improves the ability to produce 10barg steam and reduces the amount of external steam and saves energy.

(3) Application cases

Evonik Specialty Chemicals (Shanghai) Co., Ltd. Optimization of chloride ion concentration in the circulating water system HCN unit 2 water consumption reduction optimization project.

1) Implementation content and cycle: Use existing idle heat exchangers and 10barg steam condensate from downstream units to preheat the inlet water to the steam drum. The heat from the downstream 10barg steam condensate was originally not utilized, and was directly returned to the general condensate recovery system for use as boiler water for the steam drum. The implementation cycle is one month.

2) Energy conservation and emission reduction effect and investment payback period: Before the transformation, the amount of steam produced per ton of HCN produced by 10barg =16015/2315.4=6.917t/t; after the transformation, the amount of steam produced by 10barg per ton of HCN produced by 10barg =24921/3364.7=7.407t/t. An additional 10barg of steam can be produced per year =(self-produced steam per ton of product after transformation-self-produced steam per ton of product before transformation)*HCN production before transformation =(7.407-6.917)*2315.4=1134.546t。The enthalpy of 10barg saturated steam is 2777kJ/kg, so annual heat savings =1134.546*2777=3150634.2MJ; converted coal volume =3150634.2MJ*0.0341kgce/MJ/1000=107tce。

(4) Potential for replication and promotion, energy-saving potential (payback period)

This technology is temporarily used in some enterprises in the chemical industry. The implementation cycle of this technology is short. From this point of view, the energy-saving effect is general and the scope of technology application is relatively narrow. However, the technical transformation method is safe and reliable, and can be considered for implementation.