The View from a Process Engineer

Subtitle: Seven Steps to Good Evaluation
by Roger Sowell [1]

This article delves into the world of one of the most practical of all engineering disciplines: the chemical process engineer.   I hope to explain how we process engineers do at least some of the things we do, and why.  The examples shown here may have applicability to those who read and write on subjects such as climate change, nuclear power, renewable energy, water shortages, and many others.   All of the just-mentioned subjects are found on SLB.  (see notes and references below)

First, what is a chemical process engineer?  As I am one (as well as being an attorney at law), I can say that it is a person with a degree in chemical engineering who practices his or her engineering skills in process plants.   Process plants encompass quite a variety of industrial plants, such as petroleum refineries, natural gas plants, petrochemical plants, basic chemical plants, air separation plants, synthetic fiber plants, agricultural chemical plants, agricultural or crops processing plants (i.e. corn refineries that produce ethanol), synthetic fertilizer plants, soaps and detergents plants, adhesives plants, and many more.  My own career to date has given me first-hand experience in many of those categories, including petroleum refineries (of four types), natural gas plants, petrochemical plants (of many types), basic chemical plants, and air separation plants. 

The process engineer (leaving off the word 'chemical') typically addresses a problem or considers a new idea via a seven-step process.  These are, in order, 
1) is it physically possible, 
2) can it be made safe, 
3) can it operate reliably over time, 
4) can environmental impacts be mitigated, including post-operating life cleanup, 
5) can it make a profit, 
6) can it compete for scarce capital resources, and 
7) is it the best among the available alternatives.

Each of these steps is discussed below.   It is important, to a process engineer, to take the steps in order and not skip any steps.  

Physically Possible

This step may appear unnecessary, even ridiculous, but it is amazing (to me) how many people (typically non-engineers) who believe in and then advocate for processes or an article (meaning a thing) that violates one or more of the laws of physics.  Consistency with the laws of physics is the meaning in this context of "physically possible."   One sometimes hears, for example, that "everything is possible."  That is just not true.    There are many, many laws of physics, chemistry, and thermodynamics, that are immutable.  As I mention in my speeches, no one has ever found a violation of the Second Law of Thermodynamics.  I encourage the students and practicing engineers at my lectures to notify me at once if and when they encounter a Second Law violation, because I want to congratulate them, and be the one that notifies the Nobel Prize committee on their behalf.    Once a potential idea, or problem solution, is examined and found not to violate any physical laws, and only then, does the process engineer move on to the next step. 

Can It Be Made Safe

Safety in a process plant is not only required by law, it is critical to success.  Success may be defined in many ways, but in this context it is sufficient to have success mean long-term profitability.   This ties in somewhat to the next step, reliable operation.  An unsafe plant typically has unexpected production disruptions, perhaps explosions and fires, process areas that will not function, injured or killed employees, and a host of other undesirable outcomes.   

The process engineer examines the potential idea and evaluates the safety aspects.  There may be, for example, high temperatures, high pressures, corrosive or abrasive materials, toxic gases or vapors, and unstable chemicals that could violently expand, explode, or spontaneously ignite.  Other dangers could include very low temperatures, a tendency to solidify and block the flow, or emissions of dangerous radiation.  This is only a partial listing of the many and varied dangers that exist in a process plant.  There may be design or operating decisions that can eliminate the safety concerns, or mitigate them sufficiently to move on to the next step.   If the safety concerns cannot be overcome, the process engineer stops the evaluation. 


Reliable Operation Over Time

A process plant must operate reliably over time to be useful and profitable.  The question is how to define "reliable."   Process engineers usually define reliability by a percentage of time that a plant operates.  Operating ninety percent of the time is a typically acceptable reliability.  A process plant typically must be shut down at intervals to allow equipment to be repaired, cleaned, or have other services performed.   Plants that operate with frequent but unplanned shutdowns have a low reliability and will suffer a reduced profitability.  Profits are decreased as production decreases, from increased cost of repairs, and sometimes from re-processing unsuitable production.   A process can have multiple negative impacts where unreliable operations combine with unsafe conditions, as above.  Only where an idea can be designed and operated with sufficient reliability does the process engineer move to the next step. 

Environmental Impacts Mitigated    

A modern process plant must meet certain environmental requirements as defined in a multitude of laws.  An idea for a new process must be evaluated for environmental impacts.  There are at least three ways to eliminate or mitigate environmental impacts, including capturing and properly disposing the pollutants, dispersing the pollutants so that any toxicity is reduced or eliminated, and designing the process so that the pollutants are not produced at all.  This last means is sometimes known as "green chemistry."  

The process engineer examines the various regulated pollutants and evaluates the available means to meet the emissions requirements.   The concept of Best Available Control Technology, or BACT, is common in the environmental world.   As examples of "capture and dispose", toxic dusts may be captured in a filtering system, gaseous pollutants may be physically absorbed or chemically converted to benign chemicals, and liquids that have objectionable acidity or alkalinity (low or high pH) can be neutralized.  

Dispersing pollutants is generally a last resort, but such systems are occasionally allowed.  Examples include saline brine from desalination plants where the saline brine is introduced gradually and at multiple points into the ocean, treated water from a waste-treatment plant is also introduced slowly and over a wide area into a body of water (the Pacific Ocean receives treated water from a large waste treatment plant on the coast near Los Angeles, California), and tall smokestacks are required to allow the wind to disperse emissions. 

Environmental impacts must include mitigating any impacts when a process plant is shutdown after its viable life expires.  The US history is replete with hundreds of petroleum refineries and various chemical plants that have shut down permanently.  Many of those sites required extensive and costly mitigation to clean the soil.  Other process plants may have toxic areas that require special remediation.  

Only where the process engineer can determine acceptable ways to design and operate a plant that meets all the environmental requirements does the next step occur.     

Operate Profitably

The goal of (almost) every process plant is to make a profit, and a process engineer evaluates each idea with that in mind.  Where the idea is physically possible, can be made adequately safe and reliable, and meets environmental requirements, the process engineer examines the potential profitability.  This almost always includes an evaluation of capital costs, operating costs, and expected revenues.    Importantly, an idea that requires a lengthy construction period will also incur substantial financing costs.  

Many economic aspects of a new idea will be evaluated, including considering various sizes to take advantage of economy of scale, possibly modularized construction, competing technologies (if any exist), fees or royalties, plant location with respect to feedstocks and markets, plus many more.  It may be possible to improve profit for plants that have high electrical power requirements when they can be located near sources of low-cost electricity, such as hydroelectric dams.   

A key aspect is the cost to achieve improved reliability, especially long-term reliability due to corrosion.  Process engineers understand that corrosion is a function of the material chosen for the various pipes and equipment (note, there are also many other aspects that impact corrosion).  It may be possible to build a plant that does not corrode, if one had unlimited money and constructed the plant with titanium.  At the other extreme, one could build a plant of carbon steel and replace the various equipment and pipes just before the corrosion renders them unsafe and unreliable. 

The process engineer evaluates all the above, and many others, to determine the likely profitability of the new idea.   Several measures of profitability are usually calculated, with one of the most commonly used being the simple payout time.  A process engineer simply divides the capital cost by the annual net income (revenues minus operating costs) to obtain the number of years that would be required to pay off the capital cost.  For example, a new idea that would cost $10 million to install, and has $2 million per year net income would have a 5 year payout.   

Only where the simple payout time is sufficiently small, perhaps 2 or 3 years, does the process engineer move on to more sophisticated calculations of profitability. 

Compete for Scarce Capital Resources

Next, a new idea is evaluated against other potential ideas or projects.  It is common that only a finite capital budget exists, but the combined cost of the numerous ideas greatly exceeds the capital available.  The process engineer then must evaluate the various new ideas and select those for implementation.   The selection criteria and process may be complicated and require careful evaluation from many people in the organization.  

One criterion that a process engineer uses is the simple payout time from above.   Projects with shorter payout times almost always win over those with longer payout times.   


Best Among the Available Alternatives

The final step taken by the process engineer may appear to be identical, or similar, to the Compete for Scarce Capital Resources step just above.   However, in this context, the process engineer considers the overall wisdom of proceeding with the new idea.  Even if the new idea could be built according to all the above criteria (physically possible, safe, reliable, environmentally adequate, profitable, and more profitable than competing ideas), the process engineer considers whether the new idea should be built.   

There may be compelling reasons one might not want to build the new idea.  Perhaps the new idea consumes resources that could be used in a different way or for a different purpose.  Natural gas, for example, has been decried as a heating fuel and as a power generation fuel because it has great value as a building block for pharmaceuticals, agricultural chemicals, and synthetic fertilizer.   Coal as a resource is also limited to approximately 50 years at this time, with its primary use as power generation fuel.[2]   It might be wise to reduce coal use as a power plant fuel and use it instead as a petrochemical precursor.  

Another aspect is anticipated government regulation that would cut short the operating life of a new process plant or idea, such as occurred with mercury-based chlorine plants, plants that produced certain refrigerants, plants that produce lead-containing products, and plants that produce asbestos-containing products.   

Application to Other Areas

The above discussion shows seven steps employed by process engineers.   These steps are proven over many decades.  But, are they applicable to non-process plants?  The list at the beginning included climate change, nuclear power, renewable energy, and water shortages.   Each is discussed below.  

  -- Climate Change

In climate change, the science is so shaky, so uncertain that it scarcely deserves consideration. [3] [4] (see link and this link).   When one considers how the climate data was and still is tortured, how definitive statements of man-made climate change are made - and then revised - and then revised again and again, how modern instruments with global reach show zero warming for almost two decades, how the best "climate models" disagree with modern temperatures, it is a wonder that climate change is considered a problem in the first place.   Yet, solutions to any actual global warming, and more importantly, global cooling, can be addressed via the above seven steps.  One must, first, reliably identify whatever is a substantial factor in causing global warming - or cooling.   To date, global warming advocates believe that increased carbon dioxide in the atmosphere is causing unstoppable global warming.  There is no evidence to support that belief, however.   

If, and this is a big IF, it becomes necessary to reduce carbon dioxide inputs into the atmosphere, or remove some from the atmosphere, chemical engineers already know that it is physically possible to do so.  Safety is a major concern, especially for the processes that capture carbon dioxide and store it in liquid form deep in the earth.  A leak of liquid carbon dioxide into the atmosphere could and likely would suffocate thousands, if not millions of people.   Process plants that remove carbon dioxide from furnace exhaust stacks have existed for many years, and a modern plant is now running near San Antonio, Texas.   Reliability is not a major issue for these plants.  Environmental compliance is also not an issue, other than the massive leak from storage described above.  However, the cost to build and operate is a problem at this time.   The major issue, though, is whether the great cost to build enough plants to make a difference is justified, considering the questionable science surrounding the entire climate change and human contribution to any historical warming.  

   -- Nuclear Power 

Nuclear power is a frequent topic on SLB, and creates great disagreement and acrimony between proponents and opponents.   As readers of SLB already know, my position is a nuclear opponent.  The 30-article series on the Truth About Nuclear Power shows many excellent reasons why nuclear power plants should never be built. [5] (see link)

Yet, nuclear proponents continue with their beliefs that nuclear power is safe, affordable, and desirable.   Nuclear power can be considered as two categories: proven and unproven technologies.  As proven technologies, there are boiling water reactors and pressurized water reactors (BWR and PWR, respectively).  Unproven technologies include thorium, fusion, high temperature gas reactors, and small modular reactors.   

The arguments made by proponents for expansion of PWRs is that newer models are less costly and safer.  Some even argue for relaxed regulations, and abolition of lawsuits during construction.  Applying the seven steps, it is seen that the reactors are physically possible, but clearly not safe and not very reliable - especially as the plants age.  Environmental risks and damage are very great, with highly toxic nuclear waste emitting dangerous radioactivity for hundreds and thousands of years.  Costs to build have not been reduced but instead keep increasing, even though huge plants are built to achieve economy of scale.   Finally, competing technologies for producing electrical power make nuclear plants not the best choice, including natural gas and renewable energy.   

Unproven technologies barely pass the physically possible test, with fusion as yet only a theoretical but not demonstrated concept.[6]  Thorium plants also are physically possible but have major safety, reliability, cost and environmental concerns.[7]  The same is true for high temperature gas reactors [8] and small modular reactors.[9]  A major concern for thorium-based nuclear plants is the corrosion and cracking in the metallurgy that contacts the molten salt.  Every heat exchanger with tubes will eventually leak, with material at higher pressure leaking into the material with lower pressure.  The consequences of such leaks must be understood.   It is astonishing to me that a great number of nuclear proponents simply ignore this basic fact of process engineering.  

The final verdict on nuclear power is that proven technologies are vastly uneconomic, require massive government subsidies, and leave behind highly toxic wastes that endure for generations.  Unproven technologies are even worse.  

   --  Renewable Energy 

The renewable energy subject includes many technologies, solar in its various forms (photo-voltaic, concentrated solar, and solar ponds), wind both on-land and off-shore, ocean including waves, tides, sea-surface vs deep ocean temperature difference, and currents, river flow systems, pressure retarded osmosis at river mouths, [10] and bio-mass systems including land-fill methane capture, municipal solid waste burning, and water distribution pressure recapture.  Many of the above technologies require some form of energy storage and release to provide increased value to the untimely or intermittent nature of the energy source.  [11]

Physical possibility exists for all of the above renewable technologies.  Safety is adequate or can be made acceptable.  Reliability can also be made acceptable with sufficient design and investment.  Costs are rapidly declining in most technologies as experience is gained and economies of scale are captured.  Economy of scale exists for both larger individual units, and for mass production, and for single-events such as building transmission lines.    The lack of environmental impact, or very low impact, makes renewables especially attractive.  The eternal nature of the motive force, the sun, the wind, ocean waves, tides, and currents, and the essentially eternal production of municipal solid waste also make renewables especially attractive.  As installed costs continue to fall but costs of other forms of electric power increase, renewable energy plants become ever-more attractive.  

    -- Water Shortages

Fresh water in adequate amounts is a greater and greater concern, even though some areas experience heavy rains and floods.  Providing adequate fresh water essentially reduces to three technologies: building dams and storage reservoirs to hold and retain water during abundant years; desalinating ocean waters; and collecting then transferring excess water from areas of abundance to areas of scarcity.  Those in the water industry also promote conservation, however that has a very limited benefit.   Pumping groundwater from aquifers to the surface is also common in many areas, however the aquifers are generally not replenished as rapidly as the water is pumped out.   Yet another (unpopular) technology is simply recycling treated water from waste treatment plants.   This last has the great risk of transmitting disease via unclean water.  

Technologies exist and are therefore physically possible for each of the three technologies (dams, desalination, and water transfer).  (for water transfer, [12] see link) The technologies are safe and reliable when properly designed, built, and operated.  Certain dams have failed with harmful or even catastrophic results, but those can be minimized or eliminated with proper attention.  Environmental impacts are hotly debated, with some claiming great harm results from building dams and desalination plants.  

The major issue with fresh water is cost, and in some cases, ownership of the plants.  Water is such a vital part of life that many consider it too precious to be privatized except in very limited and controlled ways.  However, some technologies are simply very costly at this time, especially desalination via reverse osmosis, RO, the most attractive process.  A few thermal desalination technologies also exist, but are generally less economic than electrically-powered RO.  

Conclusion

The seven steps of process engineers, physically possible, safety, reliability, environmental impact, profitability, most economic choice, and wisest choice, are used to evaluate a new idea or process plant.  These steps should be used to evaluate other areas to provide a systematic and grounded conclusion.  Having a blind and irrational faith in future innovations is not a good basis for allocating resources of time, talent, and money.  Yet, a blind and irrational faith is what many people exhibit in their writings on many topics (especially climate change, and nuclear power).  

At the same time, many people have far too little understanding of the technical and economic advances in renewable energy systems, and the associated energy storage and release systems.  

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2015 by Roger Sowell

Notes and references:  (notes and references added 4-16-2016)

[1] Roger E. Sowell, B.S. 1977 in chemical engineering from The University of Texas at Austin, has worked as a Principal Process Engineer and consultant for 40-plus years in and with more than 75 oil refineries and petrochemical plants in a dozen countries on five continents.  Clients include major and independent oil and gas companies, world-scale petrochemical companies, and basic chemical companies.  Process plant assets ranged from the $100 million range, to $10 billion and higher.  He has performed hundreds of process studies in process design, operations, optimization, and economics.   Implemented projects have a cumulative value of the low hundreds of million dollars, and cumulative benefits exceeding $1.3 billion.  He is published in Hydrocarbon Processing and CryoGas International.  He has also taught engineering students at University of California at Los Angeles, University of California at Irvine, and made dozens of public speeches.  He is also a Council Member with Gerson Lehrman Group, providing expert advice to member clients.  He is also a California attorney-at-law, in Science and Technology Law, and publishes SowellsLawBlog.   He was recently (2016) requested to defend climate skeptics in United States RICO actions.   He is a founding member of Chemical Engineers for Climate Realism, a Southern California think-tank comprised of experienced chemical engineers. 

[2] CalTech Professor David Rutledge,  "Estimating long-term world coal production with logit and probit transforms,"  International Journal of Coal Geology, 85 (2011) 23-33,  http://rutledge.caltech.edu/  -- discusses world coal deposits and economically recoverable coal. 

[3] Sowell, R.  “Warmists are Wrong, Cooling Is Coming” see link 

[4] Sowell, R.  “From Man-made Global Warmist to Skeptic – My Journey” this link.  

[5] Abbot, D. "Is Nuclear Power Globally Scalable?" Proceedings of the IEEE, Vol. 99, No. 10, pp. 1611–1617, 2011,  see link)  also Sowell, R.  “Truth About Nuclear Power – Conclusion” (see link),  -- Abbot discusses 15 reasons that nuclear fission power is not viable in the long term.  

[6] Lawrence Livermore National Laboratory LIFE,  Laser Inertial Fusion Energy.  See link, also  Sowell, R.  “Power from Nuclear Fusion”,   see link  -- Sowell's summary of the LIFE process: Fusion is proceeding in research but has so many drawbacks it is almost a tragedy.  LLNL plan to split water into hydrogen and oxygen, isolate deuterium from normal hydrogen, freeze the deuterium, make spherical pellets of the deuterium, then load the sphere into a special chamber where high-powered lasers blast simultaneously on the sphere’s surface to induce a fusion reaction at the sphere’s core.    If it were not published by a US national lab, this would be the stuff of comic books and a mad scientist. 

[7] Idaho National Laboratory, “Molten Salt Reactor,” see link  also Sowell, R.  “Thorium MSR No Better Than Uranium Process”   see link 

[8] Nuclear Regulatory Commission, “HIGH TEMPERATURE GAS-COOLED REACTOR (HTGR) NRC RESEARCH PLAN” (2011)   see link  also Sowell, R.  “High Temperature Gas Reactor Still A Dream,” see link

[9] World Nuclear News, 2014, “Funding for mPower Reduced,” see link also Sowell, R.  “No Benefits From Smaller Modular Nuclear Plants,” see link

[10] US utility patent 3,906,250, also  Sowell, R.  “Renewable Energy from River Mouth Osmosis,”  see link

[11] “Nobel Prize in Chemistry, 2000: Conductive Polymers” see link,  also Sowell, R. “This Battery Is A Game Changer,”  this link  -- BioSolar's novel battery with halogenated polyactylene cathode is to provide double the kWh capacity, less weight, fast charging, and at one-fourth the cost of commercial batteries used in the Tesla all-electric cars.  Other uses include grid-scale electricity storage at affordable cost.  

[12]  Cohen, Lorraine Y. “Mid-west floodwaters, an ignored national resource,” see link, also   Sowell, R.  “Solution for Water in the West – NEWTAP,” see link  -- Sowell's concept for a national water transfer system, pipeline or canal, is described to economically transfer excess water from the Missouri River to Arizona's Colorado River. 

Unexpected Results From Computers

Subtitle: If A Human Can't Find It, The Result Is Unexpected

Computers are sometimes discussed as slaves to their programmers; that is, they produce only the results the programmer wanted when he (or she) wrote the software that runs in that computer.   I have discussed this before on other forums, and this article addresses some of my experience in this arena. 

My qualifications to discuss computers and software programming are as follows: software development, design, debugging, and various sorts of computer programming since 1971 (44 years at this time), from simple BASIC, Hewlett-Packard's programming on HP-35 pocket calculator, FORTRAN of various vintages (starting with FORTRAN 66 on IBM mainframes), Artificial Intelligence software in LISP and neural networks, Lotus 123 and MS Excel (tm), to html and similar programming on modern internet applications.   Computing platforms covered a variety, such as IBM mainframes, CDC machines, programmable pocket calculators, desktop PC (personal computers), and modern laptops. 

The primary purpose of my programming efforts has been related to chemical engineering tasks, where very large databases from a process plant running 24/7 provide information that must be retrieved, analyzed, processed, and results returned in a timely manner for appropriate decision-making.   Also, very complex oil refining, petrochemical, and inorganic chemical process unit simulations (including kinetics in reactor systems) were developed and enhanced - including various forms of optimizers (e.g. LP, successive LP,  and open-equation).   In short, computers and software are merely tools to the chemical engineer, not our reason for living.  We have real problems to solve in the real world, with (at times) hundreds of millions of dollars at stake (or more).  There are almost always time constraints in the problems that require a quick solution, such that a program that runs too long is totally useless even if it provides the correct answer.   The process unit conditions will have changed far too much for an answer to be useful.   Time frames for computer solution can be measured in hours, but often a few minutes is required, and on rare occasions, a few seconds.  

So, do the computers we use provide predictable, unsurprising results?  Are they truly slaves to their programmers?  No.   Chemical engineers know very well that our software provide unexpected results on many occasions.   This is a hard concept for many to grasp, perhaps because they have been conditioned to believe that a computer merely adds 1 plus 1 to obtain 2, but does it very, very quickly.  And, I agree that computers can and (sometimes) do add 1 plus 1 to obtain 2.  And, they do that very, very quickly.  

Examples of unexpected results follow.  One arena is in optimization of complex process units.  Another is recognition of patterns, such as "this event X always happens after that event Y occurs, but only after Z time passes from event Y."  

Complex process unit optimization.  

Process modeling and optimization is sufficiently important in chemical engineering that, for example, a session at an AIChE conference was held recently (see link), with the session description as:

"Modeling is the art of simplification of complex physics underlying the chemical processes to account for observed phenomena and make falsifiable predictions. A good predictive model provides the basis for optimization of objective function in a multi-parameter space. This session invites talks that elucidate the practice of model building, the challenges involved in optimizing validated models and reduction of optimized results to practice."

In addition, a major division of AIChE is devoted to computing and optimization, the CAST division (Computing And Systems Technology Division) (see link).  Their description reads:

"The CAST division provides relevant programs for AIChE members who share interests in computing and systems technology, especially in the analysis, design, and control of process and management systems. CAST also coordinates the Institute's activities with other societies active in this field."

Many other conferences, seminars, webinars, books, etc. are devoted to optimization in chemical engineering (see link). 

The unexpected results occur when the process model, or process model with an optimizer produce a solution that a human could not have produced, especially within the timeframe required.  Some may argue (and many have) that this is a matter of semantics, that the computer's results are within the realm of possible outcomes that the programmer allowed the computer to explore.   The argument appears to be that, given enough time, even a human could have found the same solution.  However, that defeats the purpose when, by definition, a solution is worthless if not produced within the required time constraints.  

One personal experience follows, of an unexpected result in a simulation of a petroleum refining process unit; a vapor-recovery process for a Fluid Catalytic Cracker (FCC) unit in a large, integrated and complex refinery in the US.  There was no chemical reaction in this process, merely five inter-connected towers with vapor-liquid equilibria, mass-transfer, heat-transfer, mass recycles, heat recycles, and absorption, all constrained by the typical issues of pumping capacity, compression capacity, heat exchanger capacity, and tower diameters.  The goal, or objective function, was to maximize unit throughput without undue loss of valuable components to a fuel gas system.   The process unit was simulated on an industry-standard process flowsheet software, then optimized with the internal optimizer.  Manipulated variables included the lean oil flow rate into the primary absorber, sponge oil flow rate into the sponge absorber, total feed rate, pressures, temperatures, and various heat inputs and removals.  

In this particular case, conventional, prior "wisdom" held that the lean oil flow rate was to be minimized - reduced to zero - because the lean oil material consumed energy due to being recycled.  However, the simulation and optimizer showed that the energy savings were very small while the value of increased feed rate due to a non-zero lean oil rate was many times greater, indeed, extremely valuable.   The solution was implemented with the predicted results being measured and then confirmed.  (note the "... falsifiable predictions" wording above; this lean oil optimization certainly qualified).   So, was this an "unexpected result?"   I maintain that it was, because the then-existing management believed the path they had followed was optimal until the new operating paradigm was presented and implemented.  They were quite impressed when the FCC unit was able to process a significant increment of feed (approximately 10 percent more per day).  

Other examples of unexpected results are very common, almost too many to mention.  Another refinery used a computerized kinetic simulation and optimizer on their FCC plant and found they could increase feed rate and conversion to a much more profitable state.  The same has been done many times on other process units.  

Pattern Recognition 

As mentioned above, process plants, including oil refineries, have databases with large amounts of data.  A process engineer routinely extracts data from the database and performs analyses to follow the progress of the unit.  There may be catalyst deactivation, heat exchanger fouling, distillation efficiency reduction, among many other parameters that change rather slowly over time.  Other changes are more rapid, sometimes requiring only minutes or even seconds to appear in the data.   Where a pattern can be recognized, a good engineer can and should determine the cause.   Indeed, it is fairly simple in these days to use a data-mining software to rapidly evaluate thousands of variables in pairs and other combinations to determine the extent of any correlation.  In engineering, especially chemical engineering, linear fits are possible, but the physics of the process dictate that many times, a log or exponential, or quadratic fit are indicated.  

An example from personal experience follows.  In a complex oil refinery that processed heavy oils in a Delayed Coker Unit (DCU), and processed the virgin and cracked gasoils in a FCC, data analysis found a pattern:  the cyclical production of heavy coker gasoil created an undesirable cyclical change in FCC operation.  Simulation and optimization on the FCC showed that a better operating strategy was to store the coker gasoil for a short time rather than pump the coker gasoil as it was produced into the FCC system (note, there was a gasoil hydrotreater upstream, as usual).  A steady flow of coker gasoil allowed the FCC controls to more easily optimize the unit; in effect, the control system was always "hunting" for the optimum as the coker gasoil rate fluctuated.   This result was contrary to the established "wisdom" that it was more profitable to minimize all storage, and run intermediate streams between process units right away rather than into storage and back.  The solution was presented, then implemented with great success.  The result was unexpected in the eyes of the then-existing refinery management.    

(Note: this is entirely consistent with my career as a process consultant; many times the conventional "wisdom" was false, based on invalid original assumptions, or the previously valid  assumptions had changed materially.  One refinery with a Hydrocracking Unit told me and my colleagues that their unit was optimized, thus there was no need for us to examine it.  I asked when the latest optimization had been performed, and the reply was "a few years ago after startup."  That refinery made a substantial increase in profit after being shown why a Hydrocracker Unit optimization should be performed on a periodic basis.)

Conclusion

It has been shown that unexpected results from computer software indeed exist, both for complex process unit optimization and for pattern matching.  Other categories also exist, which may be the subject of future articles.  

Roger E. Sowell, Esq. 
Marina del Rey, California

copyright (C) 2015 by Roger Sowell

More Thorium Silliness

Just a few thoughts that came to mind while reading comments on WUWT, the latest puff-piece on Thorium-based nuclear power plants. 

First, very few commenters have a grasp of what a molten salt is or does, especially when that molten salt contains radioactive thorium and uranium and other fission products.  

One comment, in particular, shows a vast ignorance of economics. claiming ". . . near-free (sic) and unlimited electrical power ($0.03/kWh), which will gut the remaining industrial sectors of Western economies. . ."  This refers to thorium-powered nuclear plants built in China.   The 3 cents per kWh might be the fuel and variable operating cost, but certainly does not include amortized capital costs.  As shown previously on SLB, a molten-salt reactor using liquid fluoride salts will cost much more than the present generation of uranium-powered pressurized-water reactors, and those cost approximately $10,000 per MW or more.  The per-kWh cost just for the capital cost would be approximately 25 cents, depending on how much state subsidy is applied to the capital cost.    Note: apparently "forgetting" to include the capital costs is a favorite ploy of nuclear proponents, because it allows them to compare (barely favorably) a nuclear plant's "cost" to natural gas.  

Another clueless commenter states ". . . there isn’t really much for the CHinese (sic) to do except size up the design. . . "  This particular commenter claims to be ". . .a design engineer who worked on projects for nearly 40 years. . ."   The "size up the design" refers to scale-up of a thorium molten salt reactor.   As I wrote elsewhere on SLB, scale-up from the pilot plant size at Oak Ridge to a full-scale commercial plant of 1,000 MW electrical output is a massive, daunting task.  (see link)  In pertinent part: "Scale-up from ORNL size (7 MW thermal) by 500 times is an enormous challenge.   Note that scale-up with a factor of 7 to 1 is a stretch, yet such a factor (using 6) requires four steps (40, 250, 1500, and 3500) to use round numbers.   Each larger plant requires years to design, construct, and test before moving to the next size, and that is if the larger design actually works the first time."  

The same clueless commenter on scale-up added to his list of errors with this:  ". . .corrosion problems that some rag on about . . . were all but solved. . ."   This refers to the very real corrosion and cracking in the reactor material, in fact, any material that touched the hot molten radioactive fluoride salt.  A material was developed and tested, but not for the 40 or more years with multiple heating-up and cool-down cycles that a commercial reactor must withstand, not to mention any vibrational stresses caused by any earthquakes.   The Oak Ridge National Laboratory "developed (in 1977) an improved and very expensive alloy Hastelloy N for nuclear applications with molten Fluoride salts.   In tests, Hastelloy N with Niobium (Nb) had much better corrosion resistance to molten fluoride salts."  (source: link just above from SLB article on thorium molten salt reactors).  

There are many other, equally silly comments. 

Roger E. Sowell, Esq. 

Marina del Rey, California
copyright (C) 2015 by Roger Sowell

Thoughts on Graduation and Starting Engineering Career

Subtitle: Go With What You Know

This article is for the new engineering graduates, but also applies to those with a year or two of industrial experience.   Some of this may seem quite obvious, but perhaps some will be useful. 

I recently was invited to speak for an hour to the AIChE student group at University of California at Irvine, or UCI.  The topic was Engineering Ethics.  During the question and answer period afterward, I was asked what was the most unexpected thing I encountered after graduation.  My reply was, I did not expect to be so unprepared for the variety and depth of topics in the industrial world.   I gave a few examples to illustrate.

My engineering degree is from The University of Texas at Austin, one of the top engineering schools in the country, if not the world.  I learned what they taught, but the fact is that the engineering curriculum cannot possibly teach everything one needs to know in only 4 years of study.    The amount of knowledge that an engineer should know increases yearly as more and more fields are created (e.g. environmental engineering, bio-engineering, nano-materials) and existing fields are expanded. 

What the new engineer should know can be viewed as 1) the fundamentals are key, 2) a vast body of topics exists and should be studied, and 3) time is your ally if used properly. 

A brief side-bar on my career start: my first job was as a process engineer in a chlor-alkali plant in a medium-sized chemical company that no longer exists.  The plant is still operating, though, after being sold to other companies.   For details, the plant was designed and built by Diamond Shamrock Corporation of Cleveland, Ohio, and was known as the Battleground Plant after the nearby San Jacinto Battleground and monument in LaPorte, Texas - just east of Houston.   This was a merchant plant, in that the products were sold on the open market and not used internally by the company.   

My first problem was understanding what a chlor-alkali plant did, and how it did it.  An engineer would do well to understand what his (or her) plant does.  Chlorine, caustic, and hydrogen are produced via electrolysis of sodium chloride dissolved in water.  I did not recall that electrolytic cells were mentioned in the undergraduate courses I took, not in chemistry, nor in reactor design.   It was all foreign to me.   At that time (1977), two technologies existed for chlor-alkali plants, diaphragm and mercury cells.  The company had both types in its fleet of plants, but the Battleground Plant had the diaphragm cells. 

The solution to curing my ignorance of chlor-alkali technology was in two steps: 1) attending the mandatory safety orientation class, and 2) reading in the Perry's Chemical Engineering Handbook.   The safety orientation class gave a good overview of the chemical plant, but was mostly concerned with the dangers and toxicity of the various processes and chemicals.  The chlor-alkali plant had plenty of dangers and toxicity: deadly DC current at 800 volts and 90,000 amps in the cell room; chlorine gas is toxic and can be deadly; caustic soda even in dilute strength (cell liquor) is hot, corrosive, and can blind the eyes; hydrogen is invisible, auto-ignites, and the flame is a pale blue that is essentially invisible in daytime.  The plant also used asbestos in creating the diaphragms.  There was also sulfuric acid in one process area, with the acid strength ranging from 70 to 98 percent.   There were also the usual dangers in a process plant, steam at various pressures, fuel gas, AC current at various voltages, and rotating machinery, to name just a few.  

After gaining an appropriate respect for the hazards I would face on a daily basis, the next task was to read the Perry's, where Electrochemistry was discussed in a few pages.  However, the Perry's treatment was mostly theoretical and I was not much wiser for having read the material.  I then turned to another favorite, Chemical and Process Technology Encyclopedia by D. M. Considine (McGraw-Hill 1974).   This excellent resource had what I needed: about half a dozen pages on chlorine production, including a process flow diagram.  (readers should note the time frame, 1978.  At the time, there was no internet with vast resources.)  Finally, the plant library had design books specific to the Battleground Plant, with process flow diagrams and material balances. 

This brings me to point 1) from above, the fundamentals.  I finally had a grasp of the fundamentals of electrochemistry and how a chlor-alkali cell operated.   In its simplest form, DC current passed through a conductive brine attracts the chlorine ions, Clˉ, to the positive electrode, and the sodium ions, Na+, to the negative electrode.   The chlorine ions combine to form a molecule of Cl2, while the sodium ions combine with OHˉ ions to form NaOH.  The left-over hydrogen ions combine to form a molecule of H2.   From there, the products Cl2, NaOH, and H2 were processed, purified, and condensed (the chlorine) into products for sale or internal use. 

The new engineer must, in my opinion, gain a good understanding of the fundamentals of his (or her) assigned process, no matter what that process is.  The above outlines the steps I took to gain an understanding.  Next, the fundamentals of engineering are key to success.  No matter what field or area one is working in, the various laws apply: material balance, heat transfer, mass transfer, equilibrium, fluid flow, etc.    

Now to point 2), a vast body of topics exists and should be studied.   The list below includes a number of topics that are common to the process industries, both batch processes and continuous processes.  Budgeting, Control and Instrumentation, Corrosion, Cost Estimation, Economics (especially incremental economics),  Environmental, Equipment, Feed Specifications, HazOps, Laboratory,  Maintenance,  Metallurgy,  Operations,  Optimization, People, Pinch Technology, PFD & PIDs, Plant's Design, Project Implementation, Product markets, Product Specifications,  RAGAGEP,  Regulations, Safety,  Technical Plan, and Trade Offs.    These are the main issues that a plant process engineer will encounter.  Those working in other areas will have different issues to learn.  Engineers also work in EPC companies, Engineering/Procurement/Construction, research, catalyst development and production, technical sales, government agencies, and others.  

Point 3) from above, time is your ally if used properly.  A new engineer could, and should in my opinion, strive to learn as much as possible as quickly as possible about the areas in which he (or she) is deficient.   Time for such learning can be found by arriving an hour early to work, at the lunch break, and staying an hour after formal work hours.   A study plan can be developed that will encompass the topics.   Another way to increase knowledge is regular attendance at AIChE monthly chapter meetings where continuing education credits are given.  Many times, these meetings include a presentation or lecture by industry experts on a particular subject.   Reading industry literature, including magazines or e-zines is especially helpful.  

UPDATE: 6/6/2015 - brief expansion on the additional topics to be studied. 

Budgeting - the engineer should know that a process plant has at least one budget, there being typically three or more.  These include a) annual operating budget, b) capital budget, c) local spending budget (under the control of the plant manager).  Learning what each budget controls, the budget size, and how the budgets are prepared are all vital to understanding the plant's operation.  

Control and Instrumentation - many times, the new engineer has had a course in the basics of process control and instrumentation; if not, he or she should study this.  The basics include (but certainly are not limited to) the four basic controlled parameters: temperature, flow, level, and pressure (and note there are several others); the measurement instruments that collect the signal; the controller that processes the measurement and sends out the correction signal; the control device (usually a control valve but not always); and the actuator that moves the control device.  In addition, the engineer should understand the basics of various control schemes, and why each controller exists at that particular point in the process.  Higher (and lower) levels of instrumentation and control exist, including safety and machinery health (bearing temperatures, shaft vibration), DCS (distributed control systems), advanced process control (computerized integration of basic controls with process models including optimization and constraints).   Other areas include inferential controls, analyzer-based controls, to name just two.  

Corrosion - the measurement and management of corrosion in a process plant is extremely important, even vital.  The engineer should read and understand the basics of corrosion - it is simply a rather slow chemical reaction that (typically) removes molecules from the corroded surface and results in thinning (usually) and weakening of the material.  The corroded material may be a process vessel, a pipe, or other equipment.  Corrosion control and management may include passivating chemicals added to slow down the corrosion rate, upstream removal of corrosive molecules (e.g. sulfur and salts), and temperature control to keep the corrosion rate manageable.  Wall thicknesses are measured during periodic shutdowns.   

Cost Estimation - the new engineer almost always has some experience in cost estimation in undergraduate studies, but the employer likely has its own cost estimation philosophy and software.  

Economics (especially incremental economics) - the new engineer also likely has some experience with economics in undergraduate studies.  The process plant likely has various criteria that the engineer is required to use for economic studies, including a list of values (or prices) for each utility, feedstock, intermediate streams, products, and process unit operating costs.  Sometimes feeds, intermediates, and products prices are confidential and guarded with great secrecy.   Incremental economics must be understood, as these are quite different from average values.   It is also crucial to understand that not all energy is equal, as a BTU (or kW) saved in one area may actually have zero value.   In addition, the cost to install equipment to save energy, or increase yield, or improve product separations may greatly exceed the benefits.   Some plants have a strict guideline that no potential project is to be advanced for consideration that has greater than two years simple payout.  

Environmental - the new engineer should learn what environmental issues exist in his or her plant, with the three standard classifications of air, water, and solids.  Typically, the plant has one or more permits from state or federal agencies that list the quantity of allowable emissions for each pollutant.   Potential modifications to the plant, e.g. adding a new fired heater, may require expensive and time-consuming revisions to the environmental permits.  

Equipment - the new engineer likely has a good understanding of the basic equipment types from undergraduate work.  The plant likely has equipment that was not included in the classwork, and almost certainly has variations on familiar equipment.  As an example, there are many types of pumps (centrifugal, positive displacement) with several variations of each.  The same is true for relief valves, control valves, block valves, compressors, heat exchangers, filters, separator vessels, fired heaters, boilers, piping, fittings, turbines, electric motors, reciprocating engines, and many more. 

Feed Specifications - each plant, and each unit within a plant, will have one or more feed specifications.  The engineer should understand what each specification is, what the allowable limits are, and how that item is measured.   Equally important, the engineer should know what the ramifications are when a feed specification is above or below the limit.  

HazOps - or hazard and operability study, is an important part of a process plant's safety plan.  This should be thoroughly understood by the engineer. 

Laboratory - the plant laboratory, the samples, and analytical tests should be understood by the engineer.  The plant may have a laboratory on-site, or may send samples to off-site labs for testing.  Many laboratory tests are described by an ASTM number (American Society for Testing and Materials), or other designation.   Reference books exist that describe each test; these should be on the engineer's bookshelf and be read and understood. 

Maintenance - the plant maintenance is one of the three major organizations in a typical plant (the others are Operations, and Technical Services).   Maintenance is a vast, complicated, and essential aspect of a process plant's success, safety, and profitability.  The engineer should learn the essentials of the plant's maintenance organization and program.  Typically, maintenance is organized by craft: millwrights, electrical, instrumentation, and piping.   Safe shutdown and isolation procedures must be understood by the engineer, as well as startup procedures once the maintenance is completed.  

Metallurgy - the engineer should understand the metallurgy and other non-metallic materials used in the plant.  Typically, various metallurgies could be used in a plant, and the choice is made based on several considerations: safety, cost, durability, corrosion, and others. 

Operations - plant operations is one of the big three organizational arms in a plant (Maintenance and Technical Services are the other two, typically).  The engineer should get to know the operations staff, from the Operations Manager to Unit Supervisors, to shift staff.  Typically, the shift staff has a Shift Supervisor, each unit has a Lead Operator (or other title such as Head Operator), and Unit Operators and helpers.   The engineer should understand the role of each.   Terminology for the various operating positions can vary by industry and by plant.  For example, there may be one or more Board Operators and Outside Operators where the Board Operator remains at a computer control console in a central control room, while Outside Operators (as the title suggests) work outside among the equipment. 

Optimization - the engineer should learn as much about optimization as possible, including what optimization systems and procedures are in place, and what they accomplish.  Optimization is a vast topic.  One thing a new engineer should know is that seasoned veterans in the Operations and Technical management are usually distrusting of new optimization schemes - especially the benefits that supposedly derive from the optimizer.  

UPDATE: 6/14/2015 -  (see link) to my March 1998 article in Hydrocarbon Processing, "WHY A SIMULATION DOES NOT MATCH THE PLANT," in which process plant simulations and optimizations are discussed.   An excerpt from the article: 

". . . there are many reasons why a process simulation doesn't match the plant. Understanding these reasons can assist in using simulations to maximum advantage.

The reasons simulations do not match the plant may be placed in three main categories: 
1) simulation effects or inherent error,
2) sampling and analysis effects or measurement error, and 
3) misapplication effects or set-up error."   
The article then discusses these three categories.   --  end update 6/14/2015

People - people skills are essential to success, not just in engineering but in almost every endeavor.  The new engineer would do well to focus on what may be called "human engineering," or practical psychology.  This is a vast topic, but crucial to success.  Stating one's views in a meeting, learning how and when to disagree without offense, learning how to network effectively, all are important aspects.   Dealing with incredibly difficult people is to be expected.   One good source for process industry engineers is the "You And Your Job" series of articles in Chemical Engineering magazine (online and archived in libraries).  

Pinch Technology - the engineer should understand Pinch Technology, (developed years ago by Bodo Linhoff) and how it applies to process heat transfer and other areas.   PT has many articles and publications that the engineer can read for an understanding. 

PFDs & PIDs - the engineer likely has a basic understanding of Process Flow Diagrams (PFD) and Piping and Instrumentation Diagrams (PIDs) from undergraduate work.  The process plant will have detailed drawings of each, which should be read and studied until the engineer is completely familiar with each figure on the drawings.   (Note that PID has a different meaning in the process control context, where it means Proportional, Integral, and Derivative).  

Plant's Design - where possible, the engineer should know the basics of the plant's design - the capacity basis, the choices among various technologies, storage and inventory quantities (i.e. number of days' storage for feedstock and for products).   Unit constraints are also important.  

Project Implementation - the engineer should learn how a project is implemented in the plant, whether a capacity expansion, or other type of project.  There may be a separate group for project work, or the engineer may be expected to develop and manage a project.  The area of project management is (or can be) complicated, with construction contracts, project schedules, disruption to the existing plant, and many other aspects to consider. 

Product Markets - the engineer should understand the market or markets for the plant's products.  This could include the historic demand, projected demands, whether his or her plant is a low-cost producer or a marginal producer, and especially: how disruptive technologies could make the plant obsolete.   This last point is rather important to chemical engineers.  

Product Specifications - similar to the above on feedstock specifications, the engineer should know and understand the specifications on each product.  At times, no variations in product specifications are tolerated.  In other plants, there may be incentives for higher purity and lower prices for selling a product with lower purity.  

RAGAGEP - the engineer should understand RAGAGEP (Recognized And Generally Accepted Good Engineering Practice) and how it applies in the plant. RAGAGEP are "engineering, operation, or maintenance activities based on established codes, standards, published technical reports or recommended practices (RP) or a similar document." They "detail generally approved ways to perform specific engineering, inspection or mechanical integrity activities such as fabricating a vessel, inspecting a storage tank, or servicing a relief valve." (source: OSHA NEP for refineries, 2007)  

Sources of RAGAGEP are many. Examples are the API Standards (American Petroleum Institute), ASME Code, CCPS (AIChE's Center for Chemical Process Safety), OSHA, NEC (National Electric Code), NFPA (National Fire Protection Association), and other engineering disciplines such as ASCE (American Society of Civil Engineers).

The intent of RAGAGEP is to ensure that process plants, manufacturing plants, structures, civil works, electrical works, and other things designed and built are as safe as possible. This extends to ongoing repairs and maintenance, alterations and changes, inspection and testing.  

Regulations - the engineer should develop at least a basic understanding of the multitude of government regulations that apply to the plant.  These likely include (but are not limited to) environmental, OSHA, FTC, labor laws, and others. 

Safety  - the engineer should understand the basics of the plant's safety program.  Safety should be first, as the slogan says (Safety First).  Whether the engineer is designing a new process, a modification to an existing process, or reviewing operating procedures, safety is critical.  

Technical Plan - the Technical Plan is (or could be) a part of the Technical Services division.  The engineer should become familiar with the tasks or projects that are underway or were recently completed, and those that are contemplated for future work.  Unless the plant is recently completed and started up, the engineer will find there is a legacy of studies, projects, and reports for each that can be read and studied.  

Trade Offs - the engineer should know what trade-off opportunities exist in the plant (this is a subset of the Economics and the Optimization areas above).  Trade-offs exist for making or purchasing utilities, feedstocks, and processing or selling intermediate streams.  

-- end update 6/6/2015


Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2015 by Roger Sowell

Thorium Nuclear Reactor Not the World Savior

Subtitle: Archibald Writes Wrong on Thorium

A recent article on Watts Up With That, WUWT (see link) sings the praises of thorium-fueled nuclear power plants as the savior of the world.  The article is by David Archibald, "a visiting fellow at the Institute of World Politics in Washington, D.C."  

Mr. Archibald could not be more wrong in his assessment - with one small exception, see end of this article. 

Thorium molten salt reactor schematic
source: Idaho National Lab

As written in several articles on SLB, nuclear power in any form is hopelessly uneconomic, impractical and unsafe.  see link, and link, and link.   As a result, almost full subsidy from government is required for any nuclear plants to be constructed and operate  (see link). 

Mr. Archibald opines that fossil fuel will disappear "soon" and only thorium-based nuclear power will be available.   He states that solar and wind will be unable to provide power, especially economic power.  

He states that a 250 MWe thorium power plant would be the basis for new plants.  This suffers from the same economy of scale problem that plagues small nuclear reactors (see link).   He further makes the mistake of using overnight (estimated) cost for the fully installed cost of a plant.  He uses $3,246 per Kw for overnight cost and a plant size of 250 MWe, then states the installed cost is $800 million each.   The fact is, as written on SLB (see link), major industrial projects require far more costs than just overnight cost.  The costs associated with material and labor inflation over time, and interest on construction loans can easily double or triple the overnight costs.  Construction schedules, or time to construct, typically stretch far beyond initial estimates, with actual time from start to startup being 8 to 10 years or more.  

Now, as to what Mr. Archibald got right.  He correctly stated that coal will run out.  His timetable is off by a couple of centuries, but he is correct that it will run out.  As earlier stated on SLB, the facts that coal will soon run out, and coal presently provides almost one-half of the world's electricity present one of the biggest challenges of our times.  Perhaps, it is the single biggest challenge.  

The alternative to coal is not nuclear, as Mr. Archibald states, but the vast amounts of free, renewable, zero-pollution, reliable power provided by ocean currents, solar, and wind with appropriate energy storage.  Note carefully, though, that ocean current power needs no storage.  (see link) 

I have not read the comments on Mr. Archibald's article at WUWT, but they are sure to be entertaining.  And for the most part, very wrong.  

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2015 by Roger Sowell

Mars Colony - Bad Idea

Subtitle: A One-Way Death Voyage

The idea of sending men (and presumably, women) to Mars, and having them establish a base in which to live has long been discussed. NASA has a webpage on the subject. (see link)  This article, and subsequent articles, discusses the Mars colonization issue from the perspective of an experienced process engineer.   The conclusion is grim: A Mars colony has very little hope of success due to very difficult conditions on Mars, the frailty of humans, and inevitable decay and malfunction of processes.   Evidence is presented from a variety of sources, including Massachusetts Institute of Technology, and NASA's own studies.  

credit: NASA website

To begin with the basics: humans require several things for life.  These things include (but are not limited to) breathable air, drinkable water, palatable and nourishing food, heat or cooling to maintain the body within a narrow comfort range, medical care, sanitation, protection from intense radiation, and protection from deadly meteors that fall from the sky.  For a colony to be self-sustaining, basic biology dictates that a sufficient number of unrelated people be included to produce healthy children.  

The conditions on Mars are now fairly well-known: the atmosphere is unbreathable, even corrosive; water exists but requires great effort to make clean enough for drinking, cooking, and bathing; ambient temperatures range from a few moments of 70 degrees F in daytime down to minus 200 F at night; soil is likely poisonous to plant life; radiation at the surface is deadly, plus the radiation penetrates as much as 3 feet into the surface; and the atmosphere is too thin to effectively burn up meteors.   As if those conditions were not sufficient, the long journey from Earth to Mars requires prospective colonists to endure strong, inter-planetary radiation.    

Ideas for colonies generally attempt to overcome these obstacles.   There is typically some energy source to provide electricity that is then used for air production, heating, lighting, and powering various equipment.   The energy source typically is stated as solar photo-voltaic, or PV.  What is not stated is the very weak solar energy at Mars' distance from the sun, nor the difficulty create by tremendous dust clouds that obscure the sun.   How much the PV system will be degraded by wind-blown dust is not mentioned much, if at all.   Storing the limited PV-provided electricity for use at night and during dust storms is a major issue.   

Living quarters must be enclosed to keep out the thin Martian atmosphere, and retain the human-tolerant air inside.   The pressure inside is much greater than that outside, so any leaks or punctures will send precious air out into the atmosphere.  That air must be replaced.  Living quarters must also provide shielding from deadly radiation from space, and from meteors of any size that smash into the surface.   Some proposals call for cave-like living quarters located under the surface.  

One recent MIT study (see link) showed the plans for growing plants would result in a poisonous air composition within a short time due to an imbalance of oxygen and carbon dioxide, CO2. 

It is assumed by colony proponents that seeds will survive and be viable after the long journey from Earth, even after being exposed to deep-space radiation.  Studies on Earth show that seeds are detrimentally affected by ionizing radiation. 

One of the greatest problems, though, is the impact on mechanical systems and especially their lubricants, from fine dust found on Mars.  It is as yet unknown how long a system would operate before the grit in the dust causes the mechanical systems to fail.   It may be that filtration or cyclonic systems can be designed and implemented to reduce dust-related failures.  

The lack of spare parts, and additional food to sustain the colonists are issues to be considered.   It is likely that unmanned, resupply ships must be sent on a regular basis to the colony.  Given the long transit time, it will be difficult to obtain needed parts and supplies on a timely basis.  This is not like contacting an internet store and having the items appear at your doorstep the next day.   Crop failures, and critical equipment malfunctions, could and probably will cause early death for the colonists. 

Finally, for this article, the basics of biology dictate that Mars colonists should not have children.  A small gene pool would result in birth defects in subsequent generations.   Proponents might respond that that problem can be overcome with sperm banks and ova, however the technology to successfully perform artificial insemination may be far beyond that found in a Mars colony. 

UPDATE 1 - 5/31/2015.  

Regarding spare parts, some have mentioned the 3-D printers would solve that problem. That may actually be true, in a very limited set of circumstances.  Perhaps a plastic o-ring seal can be made to replace one that failed.  However, it is questionable (meaning I seriously doubt this one) that an item made of stainless steel, shaped in a forge with high heat and pounded with heavy hammers, then heat treated, and finally ground and polished to close tolerances will exit from a 3-D printer.  The same issues exist for other metals: copper wiring, aluminum castings, even bolts with their strength requirements and threads cut into their end.  

The biology issue was mentioned to me, and the proposed solution is simply to send more colonists until the gene pool is sufficiently great.   One can only wonder what the new colonists will eat, and what air will they have to breathe, and water to drink.   Plus, who will be spared from the ongoing work to devote time to caring for infants, then toddlers, then see to their education until they can be productive members of the colony.  Children are great (I have two), however in a Mars colony environment that is likely on the verge of starvation or suffocation each and every day, children may be a significant contributor to extinction. 

For more on the negative side, NASA recently noted unexpected corrosion on the rover's wheels.  This is attributed to acidic vapor rising from the surface as the sunlight warms the Martian soil.  -- end update. 

Roger E. Sowell, Esq. 
Marina del Rey, California

Copyright (c) 2015 by Roger Sowell