Mike Bird Flashcards
What does accuracy of capital cost estimation depend on?
- the accuracy of raw cost data
- design detail; to what extent is the design complete?
- time spent making the cost estimation
Types of cost estimate
- order of magnitude: based on data of similar projects; 30% error
- study estimate: based on knowledge of major items of equipment needed; 30% error
- preliminary estimate: based on sufficient data to allow the estimate to be budgeted; 20% error
- definitive estimate: based on almost complete data but before the completion of all drawings and specifications; 10% error
- detailed estimate: estimate based on complete engineering drawings, specifications and site survey; 5% error
What is fixed capital?
The cost of a plant, so that it is ready for start-up (the cost paid to contractors). This includes cost of:
- design and construction - all items of equipment, including their installation - piping, instrumentation and control - buildings on site - additional facilities such as utilities
Except for scrap value, capital costs cannot be recovered at the end of a plant’s life
What does fixed capital cost consist of?
- Direct costs
- Purchased equip
- Installation of equip
- I&C
- Piping
- Electrical equip and materials
- Buildings (including services)
- Yard improvements
- Service facilities
- Land
What does fixed capital cost consist of?
- Indirect costs
- Engineering & supervision
- Construction expenses
- Contractors fees
- Contingency
What is working capital?
The additional investment needed to start the plant up and operate it so that income can be earned e.g:
- cost of start up - raw & intermediate materials and catalysts - inventories - money for outstanding customer accounts
This is important as growing businesses have a surplus of orders but may not receive money from fulfilled orders on time and do not have sufficient capital to buy material to fulfil outstanding orders.
Most of the working capital can be recovered at the end of the project, usually makes up 5 - 30 % of the fixed capital.
What is inflation?
cost in year A = cost in year B x (cost index year A/const index year B)
Rapid capital cost estimation
- Historical costs
An approximate estimate bases on the cost of earlier projects using the same manufacturing process.
C2 = C1(S2/S2)^n where n typically = 0.6 -> 6/10 rule
This follows that if we double the capacity of a project, costs will only increase by 50%. Means it is cheaper to have a bigger plant, but don’t want to flood the market with product and reduce prices.
Rapid capital cost estimation
- Main plant item basis step counting method
Typically used when making a quick order of magnitude estimate. A model is developed which relates process parameters such as throughput, temp and pressure and the materials of construction to the total expected cost. This takes into account either the no. of main plant items or the number of functional units likely to be involved.
Wilson’s correlation
Predicts the capital cost of the plant based upon investment factors, the average cost, and number of plant items involved.
(accuracy +/- 30%)
What are functional units?
Normally a unit of operation, piping and heat exchangers are ignored as they are part of existing functional units.
What does Bridgewater correlation take into account?
The reactor conversion, in addition to the plant capacity.
What are factorial methods of cost estimation?
Based on the purchase cost of the major equipment items. Other costs are then estimated as factors of the equipment cost. Accuracy of this method depends on the stage of design that has been reacted, and the reliability of the base data.
Lang factor values, and when is it most accurate?
3.1 for solid processing
3.6 for solid/fluid
4.7 for fluid
most accurate when preliminary flow sheets have been completed and main equip has been sized.
Detailed factorial estimate steps
To improve the accuracy of the estimate, the cost factors compounded into the Lang factor can be considered separately. Most commonly used shortcut method for process plant capital cost estimation
1. Prepare mass and energy balances
2. Draw preliminary flowsheets
3. Size major items of equip and select desired construction materials
4. Estimate the purchase cost of main items of equip (PCE)
5. Calculate the total physical plant cost (PPC)
PPC = PCE(1 + f1 + f2 + … + fn)
Why is estimation of purchase cost of equip important?
As the cost of purchased equip is central to the factorial costing method, it must be determined as accurately as possible. (relationship between equipment size and cost is usually shown on a log-log plot).
Importance of estimating operating costs and what are the two types? (with examples)
Helps to determine profitability of a process. The trade off between capital and running costs is also a key and recurring theme. In addition, running cost estimation is required to enable choices to be made between alternative processing routes.
1. Fixed: don’t vary with the production rate, must be paid no matter the quantity of the product produced
e.g
- maintenance - operating labour - lab costs - supervision - plant overheads - capital charges - rent (land, equip, buildings) - rates and taxes - insurance - licensing fees and royalties
2. Variable: vary with the production rate
e.g
- raw materials - utilities (plant services) - shipping and packaging
Each plant is expected to carry its share of the company’s general operating costs, these may be:
- cost of renting offices - R&D - marketing and sales - reserves
These could be 20-30% of additional production costs.
How are raw material costs predicted?
The flow rate values obtained from flow sheets are multiplied by the operating hours or years the plant is expected to run. Operating quotations from suppliers gives the most accurate estimate, but these can be difficult to come by.
What % of total maintenance costs are plant supplies expected to be?
10%
e.g safety clothing, pipe gaskets, cleaning materials
How much of installed capital costs are maintenance costs expected to be?
10 - 15%
Operating labour
plant technicians/operators are needed to keep the plant running. Cost of this labour can be estimated by knowing the number of shifts and the time each day that the personnel are required. For 3 shifts, 5 crews are needed. Continental shift pattern typically works from 6 am -2 pm, 2pm - 10 pm and 10 pm - 6 am. Expected to be 15% of total operating costs.
Categories of labour costs
Supervision of operations: variable cost dependant on size of plant, type of process etc
Lab costs: labs needed to monitor product quality, approx. 2-4% of production costs
Plant overheads: such as general management, security, medical centres, canteens, safety or clerical staff
What does sole proprietorship mean?
Business is owned and run by one person. Few if any employees. Easy to create but unlimited personal liability and limited to the life of the owner.
Partnership
Similar to sole proprietorship but with more than one owner, each of whom is personally liable for the firm’s debt. A lender can require any partner to repay all of the firm’s outstanding debt. The partnership ends with the death or withdrawl of any single partner.
Limited liability company
All owners have limited liability to their investment and cannon be held personally responsible for debts
What is a corporation?
A legally formed entity separate from its owners and many of the legal powers of individuals such as:
- enter into contracts
- own assets
- borrow money
Its owners are not liable for any obligation the corporation enters into. Ownership in the company is represented by shares of stocks:
- sum of all ownership value is called equity
- owner of stock is called a shareholder, stockholder or equity-holder
- ^ they are entitled to dividend payments
What is the management team?
In a corporation, ownership and direct control are separate. Shareholders are the owners but have no say in daily operations. The board of directors are elected by shareholders and have ultimate decision-making authority. The CEO runs the corporation and the board typically delegates day-to-day decision making to them.
What are financial managers?
The CFO is the most senior financial manager in the firm and reports directly to the CEO. Three main tasks:
- Investment decisions
- Financing decisions
- Cash management