The gas-to-liquid volumetric mass transfer behavior has been studied using the oxygen dissolution method in a three-phase circulating #uidized-bed (CFB) reactor 140mm in inner diameter and 3.0 m in height. The volumetric mass transfer coe$cient kLa is obtained from the measured bulk concentrations of the liquid phase by means of the axial dispersion model. The in#uences of the main operation conditions, such as super"cial gas velocity and super"cial liquid velocity and solid circulating rate, on the volumetric mass transfer coe$cient are studied systematically.

The gas–liquid mass transfer behavior is studied in a three-phase circulating fluidized bed reactor of 140mm i.d. and 3.0m height. Using the oxygen dissolution method, the volumetric mass transfer coefficient kLa is obtained from the measured bulk concentration of the liquid phase by fitting to the axial dispersion model (ADM). The gas holdup and the distribution of bubble size in the bed are measured by a fiber optical probe system, then the gas–liquid interfacial area a and the mass transfer coefficient kL are calculated. The influences of the main operating conditions, including superficial gas velocity, superficial liquid velocity and solid circulating rate, are studied systematically.

The synergy effect of process coupling of reaction-reaction and reaction-heat transfer for dimethyl ether synthesis has been studied. The theoretical and experimental analyses show that the synergy of reaction-reaction is prominent and that the synergy of reaction-heat transfer is also feasible. Due to the synergy effect, CO-rich synthesis gas can be used for dimethyl ether synthesis and higher once-through conversion of CO can be obtained. Recycling and compression of the unreacted synthesis gas can be minimized considerably. Accordingly, savings will be made in energy consumption and the water gas shift reaction system, and the entire investment and production cost will decrease.

A new type of catalytic distillation column has been developed for catalytic distillation processes. The catalysts are loaded loosely in the downcomer of the new column, so that they can be replaced easily. A new type of column plate structure has also been proposed to accommodate the new distillation column. Experimental results show that the new column and plate structure have much improved performance, with high plate efficiency, low pressure drops across the plate and very good operation flexibility. The novel catalytic distillation columns could be employed to many catalytic distillation processes.

An integrated hydrodynamic mathematical model is established from experimental results and a more rigorous definition is proposed for the uniformity of the axial gas distribution in a radial flow moving-bed reactor (RFMBR). A new iteration strategy is provided for the solution of the model. Simulations show the influence of the flow structure, the reactor dimension, the design of the axial gas distributor and the operation conditions on the axial uniformity of the gas distribution. This work provides a theoretical basis and useful method for the optimum design and operation of RFMBRs.