Study On The Pilot-scale Fluidized Bed Reactor For Methyl Chloride Synthesis From Ammonium Chloride And Methanol

Ammonium chloride is a by-product in the production of soda which is an important basic chemical raw materials. The output of ammonium chloride was 8.2 million tons in China in 2009, accounting for 95% of world production. Industrial use of ammonium chloride is very small, and it is used mainly in agriculture. Only trace quantity is necessary in the soil for crops, however the content of chlorine in ammonium chloride is as high as 66%. It will damage crops, and. stack directly in the environment, not only harm the local soil, but also cause serious pollution of water and air. Therefore, it is necessary to transform low-value ammonium chloride into high-value products. It is proposed in this thesis to produce methyl chloride and ammonia from ammonium chloride and methanol. Methyl chloride can be used to organic silicane and ammonia can be reused in the process of soda production.The bench-scale experiments on the selection of catalyst and optimum of operation conditions have been carried out since 2005 in our laboratory. The object of this thesis is scaling up the process. The main work of this thesis is designing a pilot-scale fluidized bed reactor, improving it through operation, and carrying out the experiments on it.Based on the analysis of the reaction process, the principle flow sheet was firstly proposed. A pilot-scale fluidized bed reactor, a roller device for the preparation of 15kg catalyst in a batch, a fluidized bed regenerator of catalyst were designed and manufactured. Many engineering problems were solved in the experiments, such as feeding ammonium chloride, blockage in the exit pipeline, heat supplying etc, during experiments. Continuous stable hot experimental operation more than 6h was reached.Hot experiments were earried out on the reactor, and the effect of the operation conditions, such as temperature, feed ratio and resident time, on the yield of methyl chloride were detected. The methods of the prodcut analysis were also erected. Carbon deposition on the catalyst during reaction was also inspected during the hot experiments on the pilot seal reactor. The regeneration of the catalyst was conducted and the activity of the regenerated catalyst was detected. The experimental results showed that the optimum operating, conditions are:the temperature,350℃～370℃:molar ratio, 1.1～1.3:1; space velocity,330min-1. The yield of methyl chloride is up to 87.1%. The experimental data were confirmed through the carbon balance between the inlet and exit of the reactor. The carbon balance is more than 93% in the pilot experiments. The results of catalyst regeneration experiments showed that the catalyst can be used repeatly with long-term stability;...