聚氨酯合成革湿法生产废气中DMF的回收工艺

A new recovery technology is developed to recycle N,N-dimethyl formamide （DMF） in waste gas from wet type polyurethane synthetic leather industry. Given that the concentration of DMF in waste gas was as low as 325.6- 688.3 mg·m^-3, it was necessary to make sure two phases contact adequately and strengthen the mass transfer by increasing contact area and enhancing the turbulence. Therefore, two-stage countercurrent absorption and two-stage fog removing system were introduced into the technology. The top section of the absorption column was filled with structured wire-ripple stainless steel packing BX500, while the lower section with sting-ripple packing CB250Y. Total height of packing material was 6 m. In addition, there were both two-stage fog removing layer and high efficiency liquid distributor at the column top. All the operating parameters, including temperature, pressure, flow rate and liquid position, could be controlled by computers without manual operation, making sure the outlet gas achieved the national emission standard that the DMF concentration should be below 40 mg·m^-3. The whole equipment could recover 237.6 t of DMF each year, with the profit up to CNY 521×10^3.     

数值微分法确定化学反应动力学方程式

<正> 化学反应工程的一个重要内容就是根据实验数据确定反应动力学方程式,其方法可分为积分法和微分法两大类。积分法如半衰期法、试差法、无因次曲线法,一般仅适用于较简单的整级数反应。随着电子计算机的广泛应用,利用非线性方程参数推算方法,也可以解决非整数反应动力学方程,但计算量较大。微分法包括图解法和数值法。图解法如     

Gilliland图的参数变换及新关联式

本文采用x=(R-R_m)/(R+1)和y_Ⅰ=(S-S_m)/(S_m+1)作为参数,对板式塔得到关联武为y_Ⅱ=-1.12lgx;对填料塔得y_(?) Ⅱ=-1.18lgx。本式在0≤x≤1的大范围内准确成立。     

合成革生产废水中DMF的节能回收新工艺

提出了从聚氨酯合成革生产废水中回收N,N-二甲基甲酰胺的节能新工艺。该工艺充分利用现有的低压蒸汽为热媒,在现有双塔回收工艺的基础上进行改进,由一级减压浓缩、二级常压浓缩、减压精馏三塔组成,热能循环使用,比现有双塔回收装置综合能耗下降37.7%,废水可以达到零排放,所得DMF产品的纯度99%以上。该工艺运行稳定,每套装置年收益达496.19万元。