Takashi Nakane

Parameter analysis and optimization of ideal heat integrated distillation columns

Abstract Parametric analysis is performed for ideal heat integrated distillation columns (HIDiC) and comparative studies are made with conventional distillation columns. Implications of process design and operation variables are clarified and heuristics are provided for the effective process design. A generalized process configuration is suggested, which is demonstrated to have both higher energy efficiency and higher flexibilities than its original configuration. Simulation studies are conducted and the obtained results confirm the conclusion.

Operating an ideal heat integrated distillation column with different control algorithms

The operation of an ideal heat integrated distillation column is addressed. Five control strategies, namely, single loop composition control system, multi-loop composition control system, multivariable internal model control (IMC) system, modified multivariable IMC control (MIMC) system and nonlinear process model based control (NPMC) system, are design and applied to the process. Simulation results demonstrate that all the control systems are capable of keeping both end products on their specifications. The NPMC is the best one in the operation of the ideal HIDiC. It can very smoothly realize setpoint transition and efficiently counteract external disturbances. The MIMC ranks the second for the regulatory responses to feed composition disturbances have relative longer setting time. The next comes to the multi-loop composition control system. Although it works well for the operation of the ideal HIDiC, it produces relative larger oscillations and longer setting time in the system responses. The IMC can not compete with the multi-loop composition control system because it is extremely sensitive to operating condition changes. The single-loop composition control system is the worst one for the responses of the uncontrolled product is extremely sluggish.

A New Configuration of Ideal Heat Integrated Distillation Columns (HIDiC)

Abstract A new configuration for ideal heat integrated distillation columns (HIDiC) is proposed by further heat integration between its overhead product and feed. This modification makes the ideal HIDiC more self-support and imposes fewer constraints to the environment. The added heat integration is different in nature from the one between the rectifying and the stripping sections. The latter is self-regulating, while the former is not. Open-loop integrating process is produced by the added heat integration, which makes the process more difficult to control than before. It is therefore extremely important to explore the interaction and tradeoff between process design and operation. Simulation studies are conducted to evaluate the process operation feasibility and it is found that the process can be well controlled through manipulations of pressure difference between the rectifying and the stripping sections and feed thermal condition.

Mannosylerythritol lipid, a yeast extracellular glycolipid, shows high binding affinity towards human immunoglobulin G

BackgroundThere have been many attempts to develop new materials with stability and high affinity towards immunoglobulins. Some of glycolipids such as gangliosides exhibit a high affinity toward immunoglobulins. However, it is considerably difficult to develop these glycolipids into the practical separation ligand due to their limited amounts. We thus focused our attention on the feasible use of mannosylerythritol lipid A, a yeast glycolipid biosurfactant, as an alternative ligand for immunoglobulins, and undertook the investigation on the binding between mannosylerythritol lipid A (MEL-A) and human immunoglobulin G (HIgG).ResultsIn ELISA assay, MEL-A showed nearly the same binding affinity towards HIgG as that of bovine ganglioside GM1. Fab of human IgG was considered to play a more important role than Fc in the binding of HIgG by MEL-A. The bound amount of HIgG increased depending on the attached amount of MEL-A onto poly (2-hydroxyethyl methacrylate) (polyHEMA) beads, whereas the amount of human serum albumin slightly decreased. Binding-amount and -selectivity of HIgG towards MEL-A were influenced by salt species, salt concentration and pH in the buffer solution. The composite of MEL-A and polyHEMA, exhibited a significant binding constant of 1.43 × 106 (M-1) for HIgG, which is approximately 4-fold greater than that of protein A reported.ConclusionsMEL-A shows high binding-affinity towards HIgG, and this is considered to be due to multivalent effect based on the binding molar ratio. This is the first report on the binding of a natural human antibody towards a yeast glycolipid.

Evaluating control structures for a general heat integrated distillation column (general HIDiC)

Abstract The assessment of control configurations for a general HIDiC (an ideal heat integrated distillation column incorporated with a overhead condenser and bottom reboiler structure) is addressed in this work. It is found that the double ratio control configuration, (L/D, V/B) is still the best one among all the possibilities. Moreover, the pressure difference between the rectifying and the stripping sections and the feed thermal condition are expected to be consistent manipulative variables for the control of the general HIDiC. The control configuration, (pr-ps, q), appears to be a feasible one for the process operation. The performances of the general HIDiC can be substantially improved by employing efficient multivarible control algorithms.

Phase equilibria of some alternative refrigerants hydrates and their mixtures using for cool storage materials

Electric power demand for residential air-conditioning has been increasing in Japan. Development of cool storage systems which shifts this demand to off-peak period and contributes to the load leveling of power generation is necessary. The hydrate cool storage system is the suitable cool storage system because its cool storage density is large and chiller efficiency is high. In this study, alternative refrigerants HFC-32(CH/sub 2/F/sub 2/), HFC-125(C/sub 3/CHF/sub 2/) gas hydrate and their mixture were selected for cool storage materials. The phase equilibria of these alternative refrigerants gas hydrates and its mixtures were obtained. From these phase equilibria, the critical decomposition temperature, the critical decomposition pressure and the heat of formation of these gas hydrates were determined.

Producing electric power by wet oxidation of biomass ethanol

A new process for producing electric power through wet oxidation of biomass ethanol is proposed in this work. The process configuration is introduced and its energy efficiency is evaluated by using a simple process model. The advantages and disadvantages of the process are also indicated.

Characteristics of energy savings in an ideal heat-integrated distillation column (HIDiC)

Distillation columns are major energy consumers in the chemical and petrochemical industries. In order to reduce energy consumption, considerable studies have been carried out and many distillation columns have been proposed. A heat-integrated distillation column (HIDiC) is constructed in such a manner that its rectifying and stripping sections are separated, while connected through a compressor and a throttling valve. Separation is benefited by heat integration between the two sections. To provide the driving forces for heat transfers from the rectifying to the stripping sections, the former must be operated at a higher pressure than the latter. The HIDiC is expected to be more energy efficient than conventional columns, while at the expenses of some energy to raise up the pressure of the rectifying section. In this paper, it is shown by thermodynamical consideration that the HIDiC has high potential of energy loss reduction compared with conventional columns. The effects of pressure difference on energy saving are analyzed, and possibility of energy saving is found in some case studies.