Straw Mechanical Thermal Dehydration Solution Of Alkali Metal Membrane Separation And Recovery Technology

Rice straw and wheat straw are the most common agricultural byproducts in the rural area of China. Its widely distribution and huge quantity have brought a lot of handling problems, such as resource waste, environmental pollution. How to utilize this kind of biomass effectively is of great importance. While the commonly high content of alkali mineral always bring kinds of matters during combustion and gasification utilization. Agglomeration in the fluidized bed, deposition on the convention surfaces and metal erosion in the high temperature in the furnace, are usual problems, which limit the usage of straw in large-scale utilization. Straw mechanical thermal dewatering can effectively reduce alkali metals content and can minish the corrosion degree of the burnable equipments; Simultaneously fuel value of straw enhances.Straw mechanical thermal dewatering liquid Contains the alkaline metal and the organic matter richly. How to treat the straw mechanical thermal dewatering liquid and recycle resources in a more effective and economical and reasonable way, and how to realize the object of "harm-free" and " reclamation ", have been always an important item of investigation. In order to treat the straw mechanical thermal dewatering liquid and recycling resources, this thesis studies the key parameter of the process of treating straw mechanical thermal dewatering fluid with membrane, which can supply reference for actual project.In the study, the infection of pressure, temperature, pH, time and concentration to the effect of membrane treating straw mechanical thermal dewatering fluid are studied, with the results showing that using the membrane can condense the wastewater 100 times, and that the condensed water can be reused for recycling. In the Nanofiltration(NF) phase, at the condition of that pressure ( AP) =0.8MPa, temperature (T) =20°C , the wastewater can be condensed 10 times; The concentration of K ion is condensed from 102.2mg/L to 931.8mg/L, and COD from 343.5mg/L to 2519mg/L; The concentration of K ion in the initial permeated water is 1.43mg/L, and COD is 152.9mg/L; After being condensed 10 times, the concentration of K ion in the permeated water is 33.27mg/L, and COD is 491.5mg/L; In the Reverse Osmosis(RO) phase, at the condition of that pressure (△P) =1.0 MPa, temperature (T) =20°C, the wastewater can be condensed 10 times again; The concentration of K ion is condensed from 1108mg/L to 10625mg/L, and COD from 2403mg/L to 16993mg/L; The concentration of K ion in the initial permeated water is 20.05mg/L, and COD is 315mg/L; After being condensed 10 times, the concentration of K ion in the permeated water is 329.38mg/L, and COD is 5482mg/L.The study in this thesis is a preliminary research of treating straw mechanical thermal dewatering liquid with membrane. The result of this study serves as guidance and reference for the actual project of treating straw mechanical thermal dewatering liquid with membrane.