Distillation Fundamentals Expertise
There are many separation processes and each one has its best application. They include distillation, crystallization, membrane, and fixed bed adsorption systems. Occasionally the best system may be a combination of these systems fundamentals.
The choice of the best application should be based on the life cycle cost. The life cycle cost is the initial capital cost of plant along with the first ten years operations and maintenance cost. The life cycle cost should include a reliability factor, which is very important in designing any process plant equipment, reactors or separation equipment. Improved reliability has a very large impact on return on investment (ROI). Many life cycle cost only review energy, but not solvent, adsorbent, or catalyst cost because of accounting rules and this can lead to skewed economic decisions.
Distillation may be the most economical and utilized when possible. Distillation is the separation of key components by the difference in their relative volatility, or boiling points. It can also be called fractional distillation or fractionation. Distillation is favored over other separation techniques such as crystallization, membranes or fixed bed systems when;
- The relative volatility is greater that 1.2,
- Products are thermally stable,
- Large rates are desired,
- No extreme corrosion, precipitation or sedimentation issues are present,
- No explosion issues are present
Distillation Project Guidelines
Revamp Projects and Grass Roots Projects have many similar steps. The major difference is that a Revamp Project should start with a high load test to identify the current equipment capacity and limits that need to be addressed in the Revamp. Most High Load Test find more than 10% additional capacity in the existing equipment.
Companies should conduct independent high load test by KLM Technology Group to certify the actual equipment capacity well before a Revamp Project. The Return on Investment of a USD $10,000.00 High Load Test can exceed 5000%.
Please review these articles on Revamp and High Load Test Procedures
404. Design Guidelines for Distillation Revamps
415. Strategies of Successful Distillation Revamps Part 1
Grass Root Project
A Grassroots Project has several recommended steps
Feasibility Study (0.5% of Total Project Cost)
A Feasibility Study should be the first step in any grassroots project. A Feasibility Study should determine the +/- 30% cost of the project, and the expected Return on Investment (ROI). Insist that the Feasibility Study only be conducted by a firm with design people that understand the fundamentals of the process. Without this experience the study will have limited value, and you will be making decisions based on flawed data.
A feasibility study, as all project cost, should be based on the total cost of the project - about 0.05%. One consideration is to conduct the study with same group that does the basic design, and let it be back chargeable to the 3% basic design fee.
Basic Design (3.0% of Total Project Cost)
The Basic Design is the Process Engineering Phase of the Project. It determines the Process Flow Diagrams, P&IDs and equipment sizes.
If the project is very large a licensor selection should be conducted by an independent firm that have experience with the different licensors. I recommend a firms like Jacobs or KLM Technology Group for this analysis.
Front End Engineering Design (FEED) (1.0% of Total Project Cost)
After the Basic Design is completed a FEED Study should be conducted for a large project. The purpose of the FEED Study should be to develop a complete Invitation To Bid (ITB) for a Lump Sum Turn Key (LSTK) Quote from an Engineering, Procurement and Construction (EPC) Company.
The FEED should not be conducted by one of the EPC firms bidding on the project. This is a large conflict of interest in the EPC firms favor. A proper ITB document will save millions in the EPC phase of the project.
EPC Firm Selection
Insure that the EPC Firm has prior experience with this type of project or the project will not be designed and built with the same quality as you might expect. Experience is important for the final end product.
Detailed Engineering (7% for Grass Roots and 10% for Revamps)
The Detailed Engineering is the Civil, Electrical, and Mechanical Engineering Design for the project.
Procurement and Construction
The next step is the procurement and construction by the EPC Firm.
The Pre Commissioning is started when the equipment construction is completed. Pre Commissioning involves the cleaning and preparation of the equipment for service.
The Commissioning is the actual placing of the equipment in service
Plant Performance Acceptance Test Run
The Plant Performance Acceptance Test Run is typically a three day test of the plant to determine if the process (basic) design guarantees are met. There are typically penalties of about 10% of the basic engineering fee, if the process does not meet the guarantees. Most plant will pass the Acceptance Test Run becuase a good design firm will add 10+% safety in their design.
The EPC Firm guarantees capacity and heat exchange, but not product purities. There can also be penalties if the plant cannot meet capacity. Most plant will pass the capacity and heat exchange because the EPC Firm will add 10% safety in their design.