Strategy

How to Increase Chemical Plant Profitability - Part 2 - Energy Efficiency

This is Part 2 of the How to Increase Chemical Plant Profitability series.

Of all the activities an operational chemical engineer has to complete, one of the most rewarding and exciting is the identification, development, and execution of energy efficiency improvement projects.

Personally I find energy efficiency projects one of the most satisfying and rewarding work to complete. It is a win-win for every stakeholder - the business saves money, the environment will thank you, and customers get a cheaper product.

Cooling Tower

Image Source: Redwood1

The reduction of energy consumption, and in turn fuel costs, is directly measurable, and is one of the most popular methods for increasing a chemical plant’s profitability.

1. Change technology

Also due to the age of some chemical plants it is often one of the easiest. Older style sites may be using out-dated technology, with the operational personnel not even realizing the opportunity and potential improvements that exist elsewhere.

Energy costs are often one of the largest costs for any chemical processing plant, particularly older style sites with older technology.

Changing from direct drive pumps to variable speed not only increases the ability to control tank levels/chemical dose rates, they also reduce the power requirements.

2. Increase instrumentation

My favourite quote which I apply to nearly every part of a processing plant is by Peter Drucker:

“What gets measured gets managed”

There are usually many energy streams which have a big impact on the energy balance but are not accurately measured. This means that people are not aware of their importance or even of their presence, depending on the size of the plant.

This could be anything from rain diluting the process liquor, or the rate of scale buildup within heat exchangers.

If the cause of energy losses can be identified and its magnitude measured it is much easier and quicker to persuade key decision makers and obtain the capital funding required.

3. Increase awareness

Large processing plants are usually so focused on production that energy efficiency is not even considered in any decision making. A lot of companies plaster the walls with posters showing the direct costs of having equipment offline to drive the mentality that having equipment offline is expensive and everything should be done to improve availability.

This idea can also be used for energy efficiency improvements - having a heat exchanger unwashed after its due date is a direct cost, and making sure everyone from the operators on the floor to the upper management knows is half of the battle.

If everyone is aware, they will all try to help out. Everyone is trying to improve the plant they are working at, so educating people about what the important things to be working on is extremely important and a powerful tool.

4. Equipment availability and maintenance

Energy efficiency does not just have to be looking at technology or equipment. Often large energy reduction can be made by changing operational practices, or maintenance frequency.

Equipment performance often degrades over time, and improves after maintenance has occured. The amount of time between maintenance is usually based on production requirements, and equipment availability. Considering energy requirements if usually ignored.

By looking at the business case including the energy costs, these ill-timed and poorly executed exercises can be improved.

5. General examples

A few general examples of energy efficiency opportunities are:

  • Improve boiler thermal efficiency
  • Increase piping insulation to reduce heat losses
  • Increase condensate recovery
  • Implement waste gas heat recovery
  • Replace old equipment with new technology
  • Reduce recycling load
  • Increase plant extraction/yield
  • Install extra heat recovery equipment

6. Specific case studies

Some more specific examples of improving energy efficiency can include:

If you have any personal examples of energy efficiency improvement or case studies please leave a comment below.

Over Control and Natural Variability

A common method for determining process stability, performance, and control is Statistical Process Control. This is a statistical method for determining the upper and lower control limits, and how much of the time the process is within these limits. From this it can be determined whether the process is within control or out-of-control.

Control charts are a visual representation of the process and the upper and lower limits. They show the difference between natural variation and one-off ‘special cause’ events.

Frequently processes fall into the out-of-control areas, and can often be caused by over control. This can be due a number of reasons, such as:

  • Trying to achieve a tighter target range than is possible
  • Control system reaction speed

“Over-control is defined as reacting to random ‘noise’ in the data, causing adjustments to be made when a better plan was to leave the process alone.”

John McConnell

If a business is trying to target a tighter target range than is possible within the natural variation, then this can cause operations to make process changes when they are not required. This creates a ‘saw tooth’ effect as the data swings from one extreme to another. Changing the control strategies so that only special cause events are reacted to can immedietly reduce these extreme swings and improve a chemical processing plant’s stability.

Every process has a natural variation associated with it, such as:

  • Temperature variation
  • Liquid Surge
  • Shift Changes
  • Equipment offline for maintenance
  • Equipment breakdown
  • Raw material grade changes
  • Control system logic

In many cases reducing this natural variation can result in significant business improvements.

There are uncountable methods for reducing process variation and overcontrol, but some of the main ideas can be merged into the following examples:

  • Reduce control system reaction rate through tuning
  • Avoid reacting to a single data point
  • Implement more advanced control systems
  • Align specifications with natural variability

If you have a process which you suspect is a victim of overcontrol, then first step is to prove this through the use of control charts. The second point is to remove the variation by stabilizing the system. I have seen this process work extremely well, and result in significant improvements in performance and cost reduction.

Some great examples of process variability and ways to reduce it can be found in MacKay and Steiner’s Strategies for Variability Reduction.

If you have any experience in reducing the impact of process variability and overcontrol, then please let us know.

How to Increase Chemical Plant Profitability - Part 1 - Overview

This is Part 1 of the How to Increase Chemical Plant Profitability series.

Although it may seem that a chemical engineers primary job is to provide technical assistance or troubleshoot difficult problems, from a managers perspective they only have one purpose - to increase the chemical plants profitability.

Source: Rob Stupka

It is also true that most projects that require capital funding need to have a business case to get approval.

Unfortunately a lot of chemical engineers, while excellent at the technical side of things, are not trained in the art of proposals, persuasion, and the development of financial analysis.

While this guide does not contain everything about financial studies, it is a beginners guide to identifying potential profitable projects, and is based on examples.

Before illustrating potential for improving site profitability, it is better to start by looking at a plant’s costs. These expenses can be generalized into the following categories:

Capital Costs

  • Equipment Upgrades
  • Expansions

Operating Expenses

  • Consumables
  • Energy - Fuel
  • Raw Materials

Maintenance Expenses

  • Parts

Fixed Costs

  • Payroll
  • Services - IT, Medical, R&D

Each of these can be reduced through the efforts of a skilled chemical engineer, as well as looking at increasing the sites income.

To see some more specific examples, the following posts complete this series:

  • How to Increase Chemical Plant Profitability - Part 2 - Energy Efficiency
  • How to Increase Chemical Plant Profitability - Part 3 - Production
  • How to Increase Chemical Plant Profitability - Part 4 - Equipment Availability
  • How to Increase Chemical Plant Profitability - Part 5 - Consumables Reduction
  • How to Increase Chemical Plant Profitability - Part 6 - Extraction
  • How to Increase Chemical Plant Profitability - Part 7 - Capital Reduction

4 Fundamentals of Processing Plant Debottlenecking

Process debottlenecking is most process engineer’s primary job. Getting extra production or better fuel efficiency is a never-ending goal, and one which gives many rewards. Every processing plant is different, and the ability to improve has numerous different possible approaches, however they all come down to 4 different fundamentals - repair, optimization, upgrading, and expansions. Which option is the most appropriate depends on a lot of factors, such as current plant condition, and availability of capital funding.

The first step in any debottlenecking project is to identify not only the current process limits but also future bottlenecks, which can include:

  • Hydraulic limit
  • Pumping capacity
  • Utilities - steam, power, water
  • Major process equipment
  • Equipment downtime and availability

Usually the plant limit can be easily identified - it is simply the reason that the target production rate cannot be achieved.

Once the limits have been identified, and often there are more than one, solutions can be developed.

1. Replace/Repair

The first step is to bring equipment back up to its original design capacity. This is often the case in older processing plants where equipment has degraded in performance over many years if it has not been properly maintained.

Improving equipment reliability will always bring rewards. Major equipment is usually maintained appropriately, but the ancillary equipment that is required to run optimally may be neglected.

  • Scale buildup, fouling restrictions
  • Equipment downtime, reliability, availability
  • Old equipment
  • Equipment failure

2. Optimize

The next most common form of process debottlenecking is through optimization. Is the problem really a lack of boiler capacity resulting in insufficiency quantity of steam or is the problem an inefficient use of the steam that is produced?

The average processing plant production rate can often be increased just be removing the ‘troughs’ or special events which cause downtime or loss of production.

Improving control logic and philosophies is another way to improve performance. It is not possible for an operator to run their area perfectly, particularly when there are other priorities distracting them. Optimizing the control logic so that certain functions are performed perfectly every time will result in significant gains over time.

  • Changing operating practices - improve washing efficiency, reduce handover time
  • Speed up pumps, conveyers, blowers
  • Introduce specialty chemicals to improve performance
  • More advanced control systems

3. Upgrade

Requiring a lot more funding than the first 2 options is through upgrading the existing equipment. If all the equipment is run as per or better than design, and has been heavily optimized, then the next possibility is to upgrade the bottleneck.

  • Install additional or large capacity equipment
  • Install additional or larger capacity pipe work

4. Expand

The most expensive form of debottlenecking is a full plant expansion. This can be through expanding the plant by duplicating the existing design or using different technology. Expansions require a huge amount of capital expenditure and design as well as construction, and commissioning.

  • Build additional production trains
  • Build additional process plants

What Next?

Eliminating one bottleneck will inevitably create another. Installing an addition pump will generally not increase total plant capacity by the same amount as other equipment cannot handle the increased flow.

There will always be another limit.

8 Ideas to Improve Profitability by Reducing Water Consumption

Water is used in nearly every industry in a wide range of applications, including:

  • Filter cake washing
  • Process dilution
  • Boiler feed (steam production)
  • Cooling
  • Dust control
  • Fire systems and safety showers
  • Housekeeping and cleaning
  • Hydroblasting
  • And unquantifiable other uses

 

 

Although it may not seem expensive, water can be very costly and the reduction in water consumption can represent significant savings for any processing plant.

 

  1. Sourcing - whether purchasing water from the government or constructing underground bores, actually obtaining water is the first cost
  2. Storage - surge capacity is handy, so the construction of tanks or storage dams is an additional expense, along with the operating and maintenance costs associated with the equipment
  3. Pumping - the transport the liquid is an additional price with pumps, pipes, electricity, and control systems
  4. Recovery - the construction and operation of sumps throughout the process area
  5. Removal - any excess water has to be dealt with, whether this is rainfall or process water, extra dams need to be developed
  6. Unwanted process dilution - any water that enters the process dilutes out the concentration of the mother liquor and can reduce the reaction kinetics
  7. Unwanted process cooling - when cold water enters the process it can reduce the overall temperature, requiring additional heating capacity to hit set points

 

One interesting exercise is to calculate the cost of water consumption. This is often a significant amount more than you would expect, but it can be used in multiple purposes, such as justifying capital work and equipment modifications, as well as used to educate operations regarding the impact of excess water.

 

“What gets measured gets managed”

Peter Drucker

 

For many plants the amount of water ingress into the process is often not measured, managed or even thought about regularly. This is particularly true of large plant with large footprints where rainwater is recycled back into the system. The first step is to measure the total amount of water being consumed and the areas it is coming from.

 

Cooling towers are a good example of a recycle...

Photo credit: Wikipedia

 

There are literally as many water saving initiatives as there are water uses. Here are some proposals to consider:

 

  1. Reduce cooling tower water make-up requirements
  2. Maximize condensate returning to the boilers
  3. Optimize wash water consumption
  4. Change wash nozzles with lower flow nozzles
  5. Convert wet cleaning to dry cleaning
  6. Optimize steam usage and heat exchange
  7. Reduce steam trap losses
  8. Install automatic timed sprays to prevent the need for continuous hosing

 

The ability to optimize total water consumption is an easy cost reduction and efficiency improving project. For many processing plants this can have the potential for many millions of dollars and should be considered in any optimization exercises.

 

Reduce Energy Losses by Monitoring Steam Trap Failure

Steam traps are used throughout process plant’s steam systems to remove condensate while losing the minimum amount of steam to the atmosphere. In large plants there can be over 1000 steam traps.

A significant amount of energy can be lost if a steam trap fails open - releasing steam to the atmosphere on a continual basis. For plants which do not have steam trap monitoring systems or preventative maintenance, these steam traps can leak for months or even years.

Steam is extremely expensive to produce, so any losses can result in huge costs very quickly. When considering the capital cost for boilers, the cost of makeup water, fuel, maintenance, and operation it can come to as much as $20 per tonne.

A single steam trap can lose as much as 15 kg/hour after failure, which depending on the temperature and pressure is a significant energy loss over time. This can be calculated by looking at the enthalpy of the stream and the number of traps that have failed.

Based on a trap lifespan of 4 years, it can be assumed that 25% of traps will fail every year, and knowing the cost of producing steam the cost of not repairing the failed traps can be calculated. This is an exponential cost over time as more and more traps fail.

Using the following assumptions, the difference in costs between not having a steam trap monitoring system and repairing all steam traps on a 6 month basis can be seen below:

  • $10 per tonne of steam
  • 15kg/hour steam loss for a failed steam trap
  • 25% yearly failure
  • All steam traps repaired after 6 months
  • $500 to replace a steam trap

In this example the $60,000 repair bill every 6 months can seem a lot just to save a little steam, and as can be seen it takes over 12 months for the savings to start to be seen. Savings of over $800,000 can be seen over a 3 year period, and saving nearly 150,000 tonnes of steam.

Introducing an extensive steam trap survey can be expensive and time-consuming, but it can pay for itself by reducing total plant losses. As steam traps fail their continual loss of steam becomes common place - often to the point where operators do not realize they should not be expelling so much steam. This can lead to a lack of urgency in repairing traps and stopping the energy loss.

Emerson were able to reduce energy losses on a major food manufacturing facility by installing wireless flow meters on steam traps. They found in a survey that 22% of the steam traps had failed for an unknown amount of time. With the installation of flow meters these steam traps could then be monitored continually, and if a leak was discovered it could be repaired or replaced - saving months of energy losses and tonnes of steam.

The use of instrumentation also introduces the additional capital cost as well as the cost of maintaining and calibrating more equipment, which may not be the preferred option of sites with limited resources. The cheaper option may be to simply set up a regular survey of all failed steam traps so that maintenance can be planned.

With ever increasing energy costs reducing steam losses is an easy way to improve process plant’s profitability by improving total fuel efficiency.

More Reading:

Understanding Steam Traps - Chemical Engineering Process

How to Handle a Crisis and Save the Day

In every chemical processing plant crisis’ occur which demand your complete attention, skill and experience to overcome. Whether it is a power failure with the potential for every pipeline to bog, or a life threatening fire, or even quality contamination that could cost millions of dollars, the ability to stay calm in the face of adversity is a significant advantage.

“Faced with crisis, the man of character falls back on himself. He imposes his own stamp of action, takes responsibility for it, makes it his own.”

Charles de Gaulle

1. Be Prepared

No-one can prepare themselves or their plant for every possible crisis, but having a plan of action prepared in advance means that you can act quickly and reduce the potential consequences. The action of preparing the plan itself is just as useful as having a plan - it provides an opportunity to develop the best strategy without the added pressure. Conducting a HAZOP means that potential problems and consequences are always considered, and turning those into an action plan ready to go is the next step.

All plants have action plans for cyclones and power failure, but there are countless other possible crisis’ that should be considered to ensure the best outcome is achieved.

If there is a potential crisis that you can foresee with devastating consequences then get working on an action plan NOW! Waiting for it to actually occur is too late.

2. Don’t be Hasty

“Time spent in reconnaissance is seldom wasted”

When a crisis occurs time is critical, but it pays to slow down and think deeply about the problem, consider all the consequences and people that will be impacted so that the best action can be taken. All too often people act quickly without thinking. Consider that thinking before acting will take less time than acting incorrectly and having to clean up your own mess, or start over completely.

3. Communicate

During times of a crisis everyone needs to be working towards the same goal. They can be working on very different aspects of that goal but their overall focus should be the same. Communicating fully is extremely difficult, and increases in difficulty as the size of the business and crisis grows. Systems should be built to ensure that communication can be achieved during difficult circumstances.

4. Learn from the Experience

All too often problems occur multiple times. It is fascinating to listen to older experienced workers who have experienced similar problems several times throughout their careers without appropriate controls being put in place to avoid them. Learning from our mistakes is absolutely critical to ensuring success as a business, a plant, and an individual.

Being cool, calm, and collected during a crisis is extremely advantageous for any engineer. It is particularly important if you are at the point in your career when many turn away from the technical aspects and focus on management. Learn how to handle a crisis now and you will have a much greater likelihood of saving the day when the time comes.

Please leave a comment if you have any advice that you have experienced after  successfully or unsuccessfully handling a crisis.

Key Process Indicators - Measuring for Improvement

“What gets measured gets managed”

Peter Drucker, Social Ecologist

It is surprising how many processing plants do not accurately or comprehensively measure some of their most important variables. This can lead to inefficiency, expensive, and process problems. There are varying reasons for this, but the main one is focus - the company is more focused on their bottom line and profitability than process. Little do they realize that running a process efficiency and minimizing raw materials consumption will almost always improve the bottom line.

Source

Another issue can be the lack or inaccuracy of instrumentation. If the primary water input does not have a flow meter, then the plant cannot identify whether any changes have occurred, and what their impact can be on the process.

“Knowledge is Power”

Sir Francis Bacon

Identifying which process variables is critical, which are important, and which can be ignored is often a valuable exercise. All the thousands of pieces of data can be summarized in just a few key process indicators (KPI), with 5 often selected to represent the entire site. These are then compared with historic plant performance or against an agreed upon target. If a certain indicator is not reaching the target, then it gives an action to follow up on.

One common approach to collaborating all these KPIs is through the use of a scorecard. Upper management may only be interested in the following pieces of information, which give them a general overview on plant performance:

  • Total daily production
  • Number of quality parameter targets met
  • Raw materials and energy consumption
  • Extraction efficiency

Each individual unit operation can have its own KPIs which when added together create the scorecard of the operational area. For example, a heat exchanger could have the following KPIs:

  • Throughput
  • Availability
  • Heat Transfer
  • Fouling Factor (UA)

Another example could be of a horizontal belt filter with washing capability:

  • Throughput
  • Availability
  • Wash water consumption
  • Final cake moisture
  • Average vacuum applied

KPIs can be used to measure the effectiveness of many areas of a business, not just the process. The employee turnover rate, total number of full time employees, salary budget, and average wage could be taken as the key indicators of a HR department.

Keeping track of each process change is impossible, but managing the key process indicators is achievable and focuses your attention on the variables which actually matter.

If you have any questions or suggestions, please comment below.

Stability - The #1 Key to Plant Performance

1

University excels in teaching the theoretical knowledge that allows chemical engineers to calculate the key performance attributes of individual pieces of equipment and the ability to analyse data. One key area which it does not focus on is the proper strategies for actually running a processing plant.

There are lots of different strategies depending on the focus of the site, whether its quality (pharmaceuticals), quantity (commodities), profitability (everywhere), or any number of other priorities. The one aspect that is extremely important, and one that is sadly lacking at a lot of processing plants is stability.

In a lot of industries a specific site is given a production rate in which the company is able to comfortably produce, as over-producing is considered a waste - there is no point producing more product than customers require. However, in commodity driven industries where there is much larger demands from customers, there is almost always the driving force from business leaders to produce as much as possible. This inevitably leads to processing plants being pushed beyond their capabilities, result in waves of production. Record production is constantly being met with ever improving techniques/control quickly followed by equipment failures as units are pushed further than they ever have before.

After the equipment failures and management seeing the lower production figures the next decision is often to push the plant hard again to ensure the production targets are achieved.

This kind of ‘see-saw’ pattern is common in some processing plants, however it makes life very difficult for operations and maintenance, as well as chemical engineers trying to run the site.

Focusing on plant stability at a production rate that the equipment is designed to handle will actually result in higher production. Although the peaks will be removed, a significant number of the troughs will as well, resulting in an average greater than before.

Being able to achieve a stable operation can be difficult, although there are many ways to achieve it:

  • Introducing more advanced control systems
  • Removing the focus from record-breaking days
  • Lowering the production target
  • Changing the ‘push’ mentality through training and education

By having a stable operation, the process noise will be removed from the data, allowing process improvements to be more easily identified, troubleshooting to be far easier, and all forms of justification to be more accurate. It also helps operations to better understand their daily tasks, and maintenance can focus on preventative tasks instead of being run off their feed with reactive work. All of these benefits add up to result in significant cost reductions and improved profitability.