CSFMB^©/CeSFaMB^TM Comprehensive Simulator of Fluidized and Moving Bed equipment

CeSFaMB provides a complete picture of the internal processes such as:

• Concentration profiles of 18 gaseous components (Ar, H₂, H₂O, CO, CO₂, O₂, N₂, CH₄, SO₂, NO, N₂O, NO₂, HCN, H₂S, NH₃, C₂H₄, C₂H₆, C₃H₆, C₃H₈, C₆H₆, Tar) throughout the bed (emulsion and bubbles) and the freeboard;
• Flow and temperature profiles of gases in the bed and freeboard;
• Temperature, rate of circulation profiles (or flow) of solid phase components in the bed and freeboard;
• Composition, particle size distribution of each solid species in the bed and at each point of the freeboard;
• At each point of the equipment, all parameters related with the dynamics of the bed and freeboard. Among them: bubble diameters, upward velocities of each phase (emulsion, bubbles, particles), minimum fluidization parameters, rate of particle turnovers, etc.;
• In the case of recycling of solid collected by the cyclones, all parameters describing such an operation, as well its effects in the process;
• Profiles of important homogeneous and heterogeneous reaction rates. This feature provides a clear picture for deeper understanding of the processes occurring at each point of the equipment.
• All engineering parameters to help with equipment design as well as optimization of operations. Among these parameters there are: carbon conversion, efficiencies, pressure losses, bed holdup, residence times of particles, rate and characteristics of entrained particles, parameters to allow verification of segregation of particles in the bed, etc.;
• In the case of boilers, important operational parameters regarding the heat transfer to immersed tubes are also provided. Among them: detailed temperature profiles of the immersed tubes in the bed and in the freeboard, flow, temperature, and pressure of produced steam, heat transfer rates and coefficients related to the tubes and bed iteration, rate of erosion of tubes immersed in the bed, efficiencies, etc.
• All process parameters to allow evaluations and studies of equipment concepts such as, for instance, use of water jackets for steam generation, which can be injected at any point of the reactor, use of gas jackets for pre-heating of air or gasification agent before it is injected into the bed.
• In the case of gasifiers, several details and parameters are also provided. Among them: “Cold” and “Hot” efficiencies, flow, composition, temperature and pressure of the produced gas at various basis (molar, mass, wet, dry), physical and chemical properties of the exit gas (heat values, heat capacity, density, conductivity, viscosity, adiabatic flame temperature in air and in oxygen).

In addition to these possibilities, the latest version allows:

• Simulating cases where two or more fuels are simultaneously fed into the equipment.
• Simulating equipment with almost any geometry. The user would be able to input various internal diameters according to the vertical position; for instance, a reactor with many conic combined with straight walls. CeSFaMB can simulate even equipment with curved vertical walls.
• Proper design of the reactor's internal and external insulation layers. The user would be able to input the thickness and thermal conductivity of various insulation layers. CeSFaMB would compute the temperatures of interfaces inside the composed layers as well as the external surface temperatures with great precision. Such would permit proper and secure design of insulations to avoid risks to the reactor steel shell.

The computational code provides several warnings against dangerous or impossible operations. These warnings are extremely important to avoid accidents or destruction of the equipment. Examples of problems more related to bubbling techniques are:

• Collapse of the bed due conditions below minimum fluidization;
• Total carrying of the particles or state of pneumatic operation;
• Eventual surpassing of softening ash temperature, which provokes agglomeration of particles and collapse of the bed. This problem could destroy the refractory insulation of the reactor;
• Slug-flow due to bubbles reaching dimensions comparable to the cross-section of the bed.
• Segregation between particles in the bed. As shown before, this process may lead to non-uniform temperatures and bring problems such as bed collapse or excessive tar concentration in the exiting gas.

Basic scheme of CSFMB mathematical model

Scheme of circulating fluidized bed equipment

 Scheme of updraft moving bed gasifier

Aspect of control panel for output page