Chemical Engineering Process Design

Design of an ammonia reactor was conceived as part of a series of item designs for an ammonia plant in Cyprus. The Chemical and Mechanical aspects of the design were considered. Optimization of these designs was studied, worked on, & discussed. The safety, environmental and legal regulations of relevant reactor regulations were followed in the design concerned.

In this study, a novel mixed refrigerant cycle (MRC) integrated with NGL recovery process for small-scale LNG plant is proposed and optimized. The proposed process can be used to produce LNG and NGL with low energy consumption. Genetic algorithm is chosen as the optimization method for the proposed MRC-NGL process. The unit energy consumption as an objective function is optimized with key parameters. The optimization results show that the unit energy consumption and the molar flow rate of the mixed refrigerants can be reduced by 9.64% and 11.68%, respectively, compared with that of the base case. The effects of several key parameters on the process performance are also investigated and discussed based on the optimization results. Furthermore, the exergy analyses of the main equipment are also presented and analyzed. The economic analysis also shows that the proposed process has a good profitability and a short payback period.

Petroleum products play an important role in different sectors of Bangladesh and Eastern Refinery Limited is the most renowned company to refine crude oil to produce different petroleum products. It produces almost 16 different petroleum products such as LPG, Naphtha, Kerosene, Diesel, AGO, Fuel gas. Though refining process consists of a wide variety of units the major part is done in Crude Distillation Unit (CDU). So, Simulation of Crude Distillation Unit of Eastern Refinery Limited Company was carried out using ‘Aspen Plus’ Process Simulator. The aim of the simulation was to compare the theoretical data with the simulated data. Design data have been taken from Eastern Refinery Limited. Aspen Plus model was developed and simulated data was validated. Different distillation curves obtained from the simulator was found similar to the expected.

Pharmaceutical corporations face rapidly rising process research and development (R&D) as well as production costs due to globalised competition. Batch production processes are
dominant in the pharmaceutical industry and have multiple advantages, including equipment flexibility, high-fidelity quality control and the ability to recall specific batches; they however suffer disadvantages such as limited heat transfer and mixing scalability and low operational asset efficiency. Continuous Pharmaceutical Manufacturing (CPM) has a documented
potential to reduce cost, as continuous production techniques can be easier to scale up and can be designed to be more efficient in terms of both solvent and energy use: therefore, it is both timely and important to explore the expanding feasibility limits of this emerging technology. The literature has been extensively surveyed in order to identify a series of candidate Active Pharmaceutical Ingredients (API) for flowsheet synthesis,
process modelling and mass balance simulation toward rapid assessment of CPM potential. Ibuprofen [2-(4-isobutylphenyl)propanoic acid], the widely used non-steroidal
anti-inflammatory drug (NSAID), has emerged as an ideal CPM candidate because it is in high global demand and can generate significant profit margins. The flowsheet is based on a published organic synthesis pathway and produces 50 kg of ibuprofen annually using three plug flow reactors (PFRs) in series,followed by a final separation for purification. Kinetic
and thermodynamic parameter estimation modelling has been employed in order to compute essential data for design, and all PFR reactors have been designed based on reported conversions of feed and intermediate organic molecules in the respective organic synthesis reactions. Theoretically computed reactor designs are in good agreement with experimental
prototypes constructed for the same organic synthesis, as well as in with previously reported CPM systems. The developed continuous final separation performs very well in accordance
with green chemistry principles, with relatively low environmental impact (E-factor = 25.4).

The current increasing production of small volume, high added value products has called
attention to batch production technologies. Although batch distillation typically consumes more
energy than continuous distillation, it provides more flexibility and involves lower capital
investment. Thus, since energy costs are not too significant in the separation of small volume of
high profit products, batch distillation is often attractive.
Available batch distillation models have appeared in the literature, ranging from very simple
approaches to more detailed. Commercial software packages such as BATCHFRAC™ (Boston
et al. 1981), BASIS (Simulation Sciences Inc., 1989) and ProSimBatch, (1992) are available
only to model batch distillation operation.
Luyben W. (1992) implemented an inferential control using a rigorous quasi-dynamic model of
a batch distillation column. Recent progress in nonlinear model-based control techniques have
made the practical applicability of nonlinear controller a true. Many of these techniques use a
nonlinear dynamic process model directly in the control law development phase (which is
performed off-line). These features are very attractive for practical implementation. Henson
and Seborg (1997) list a number of simulation and experimental studies in which this
feedback controllers were used. In this context, a nonlinear model–based strategy implemented
with commercial software is analyzed here. Therefore BATCHFRAC™, HYSYS® and
CHEMCAD® performances were tested to evaluate whether their implementation in an
inferential control structure and /or soft sensor could be attractive.
Hence, using the worldwide commercial available tools, the dynamic behavior of a batch
distillation column was modeled.

As carbon emissions become a growing cause for global concern, greater pressure has been placed on industry to develop innovative alternatives to traditional commodity chemical production. In order to investigate such an alternative, a design report has been written examining the construction and economic feasibility of a Solar-Thermal Biomass Gasification facility. This facility will serve as an alternative means of high-purity, industrial scale methanol production.

The facility modeled here utilizes 204 million pounds of corn stover biomass per year as feed stock, employs 111 full-time operators, and produces 58,300,000 gal/year of methanol end product. The plant operates in five distinct subunits. Waste corn stover enters the biomass pre-processing portion of the facility where it is ground into usable cellulose and lignin. The usable biomass is then sent to the biomass gasification subsystem, in which a series of three reactors convert the biomass to methanol. In order to mitigate the environmental impact and utility costs of the largest reactor, a solar field operating as part of the facility supplies thermal energy to the solar reactor. An amine scrubbing system purifies the waste gas stream of environmental toxins, while the final stage of product processing entails the purification of the end product methanol, resulting in a final product stream with 99.97% purity by weight. The capital cost of the facility was determined to be $300.5M.

An economic analysis was performed for plant operation in which 12.5% fixed IRR was stipulated for facility investors. This economic analysis returned a 10.8% ROI, 9.2 year PBP and $62.462M NPV based on a 30-year expected facility lifespan with a single year construction period and single year of 50% capacity startup operation. In order to obtain the required 12.5% IRR, the final product selling price was determined to be $1.69/gal methanol. This price is not competitive with the current commodity market value of $1.05/gal (Methanex, 2015). Because of the facility’s inability to ensure investors suitable returns while meeting end-product market value, it is the recommendation of this design team that the Solar-Thermal Biomass Gasification facility not be constructed. In the event that a carbon credit is granted to the facility to incentivize eco-forward industry, a subsidy of $0.21/lb CO2 avoided would be required to reduce the product selling price to market value and render the project economically viable.