Biodiesel Preparation Using CNTs-based Monolithic Catalyst

Biodiesel, as a kind of renewable alternative energy sources, has formed a huge market around the world. The biological oils after a simple methyl ester exchange reaction can turn to be so called the first generation of biodiesel, which does not contain atoms such as sulfur, nitrogen. The fuel is a kind of low environmental effect and can be used directly to supply diesel engine. At present, the popular production process mainly contain two steps, esterification catalyzed by sulfuric acid and transesterification catalyzed by sodium hydroxide, then separation by vacuum distillation. This method has the disadvantages of serious equipment corrosion and high energy consumption. In this paper, based on the characteristics of biological oil with methanol in the ester exchange reaction and according the characteristics that the reactants, the main products are heavy components, we developed a unique catalytic distillation technology route.We designed and prepared monolithic catalytic distillation component, which was a stainless steel wire mesh structure growth with carbon nanotubes on the raschig ring, then functionalized carbon nanotubes by the solid acid. Monolithic catalytic distillation component was applied to the catalytic distillation process. Reaction and separation can be finished integrally. Significant progress has been made. Our work is as follow.First, we chose the right stainless steel wire mesh as the base of catalyst for the growth of carbon nanotubes, explored the effects of different pretreatment conditions on the growth of carbon nanotubes and found the best pretreatment condition. The treated stainless steel wire mesh were placed in the growth furnace. At the same time, metallocene is added in the sedimentary carbon source gas catalytic vapor deposition as a floating method (FCCVD) growth of carbon nanotubes on the screen. The optimum reaction conditions were explored. Uniform carbon nanotube array was grown out on the stainless steel wire mesh base, which was combined with basal closely.Second, the surface of carbon nanotube array of screen component were overall sulfide and oxide surface to obtain overall solid acid materials with sulfonic acid group. By using the combined method of qualitative and quantitative spectroscopy measurement, the property of monolithic solid acid materials was characterized, which showed that the acid density of material was high, mechanical processing performance was good and its structure was stable.Third, using the distillation towers packing of above tiny catalytic,that biological oil raw materials dripped to join the reaction tower from the top and performed ester exchange reaction with rising methanol steam from downward at the surface of component. High purity fatty acid methyl ester, which was produced in this reaction, directly flowed into the reaction tower kettle. It was amazing to find that byproduct glycerol can further be turned into methyl higher product and separated from the top of the tower in this process.This process has great significance in theoretical exploration and a good application prospect, so it is worth furtherly researched and application promotion.