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A lost Maxis “Sim” game has been discovered by an Ars reader, uploaded for all

The clearly incomplete prototype can now be downloaded from

Wow. It may only be an incomplete prototype, but in a breathtaking span of time, SimRefinery has gone from a seemingly lost legend to a playable, downloadable video game. (That's its real, full-resolution opening screen, as captured using a DOSBox emulator.) And it's all thanks to an Ars Technica commenter.

We at Ars Technica are proud to be members of video game archiving history today. SimRefinery, one of PC gaming's most notoriously "lost" video games, now exists as a fully playable game—albeit an unfinished one—thanks to an Ars Technica reader commenting on the story of its legend.

Two weeks ago, I reported on a story about Maxis Business Solutions, a subdivision of the game developer Maxis created in the wake of SimCity's booming success. Librarian and archivist Phil Salvador published an epic, interview-filled history of one of the game industry's earliest examples of a "serious" gaming division, which was formed as a way to cash in on major businesses' interest in using video games as work-training simulators.

As Salvador wrote in May:

Oil refineries are really, really complicated. That’s why Chevron wanted Maxis to make them a game like SimCity, to teach the employees at their oil refinery in Richmond, California how it all worked.
To be clear, they didn’t want a game that was supposed to accurately train people how to run an oil refinery or replace an education in chemical engineering. That would’ve been incredibly dangerous. What they wanted instead was something that showed you how the dynamics of the refinery worked, how all the different pieces invisibly fit together, like SimCity did for cities.

But while Salvador gathered a lot of information about how the resulting game SimRefinery worked—and how it let users recreate SimCity-caliber disasters within its refinery simulation—he was unable to turn up any working copies. "Nobody held onto SimRefinery because it didn’t seem important," he wrote. "It was a one-off, somewhat unsuccessful training program for an oil refinery in California. In the grand scheme of Maxis, it was one of their least important titles, which has only now become an object of interest in the video game community because of its unavailability."

Challenge accepted

Unsurprisingly, the savvy, computer history-minded readers of Ars Technica took this proclaimed rarity as a challenge, and a new user signed up to comment on the article with an intriguing image upload: an apparent copy of SimRefinery on a single 3.5-inch disk, labeled only with the game's title in Times New Roman and a black-and-white Maxis logo. The anonymous user, who goes by the username "postbebop" and has so far not replied to our requests for comment, credited the disk to a "retired chemical engineering friend" who had work experience at Chevron in the early '90s After teasing a plan to recover the disk's contents and upload them to, postbebop went silent. Until today!

"Not all parts are complete" is the operative phrase of the day. Though, really, Ars Technica could use help from legitimate chemical engineers to make sense of what in this game does function properly. / Maxis / Chevron

Like other Maxis "Sim" games, SimRefinery includes a separate mini-map interface. Grab its highlighted square to move the visible boundaries of the gameplay window. / Maxis / Chevron

See that barn at the top-right? That sure looks like a SimFarm barn, doesn't it? Maxis Business Simulations was known for lifting art assets from other Maxis projects to get prototypes across the finish line, so that similarity isn't surprising. / Maxis / Chevron

Lit up at the bottom. / Maxis / Chevron

The recovered disk includes a "demo" sequence, and this functions as a predetermined gameplay demo with particularly long pauses. It's likely that this prototype was shown off in a live demo, with a speaker explaining during the pauses how the game would function as a training tool. / Maxis / Chevron

The demo reel proceeds to open and click through various interfaces. / Maxis / Chevron

I won't lie: I have no idea what these mean. I'm hopeful smarter Ars readers might share some insights. / Maxis / Chevron

Well, that explains everything. / Maxis / Chevron

Buy! Sell! / Maxis / Chevron

Time to build a plant. (Most of the interface's buttons don't work, but if you click the buttons on the wide-view window, it will toggle different options on the main window, which is how I got to this point.)

Without any budgetary notice stopping me, I prep this plant for building.

Boom! My very first alkylation plant!

Just another day at work, drumming up non-toxic, abrasive catalysts.

The anonymous Ars user returned to our comments section on Thursday to confirm that they'd uploaded the disk's contents, after an apparently annoying extraction process, to for everyone in the world to download and play. The above gallery is a peek at how the incomplete prototype version of the game functions as emulated using DOSBox. While that link will let interested users play the prototype in any Web browser, the full game download also includes an intro.bat file; booting that with an application like DOSBox will play a pre-recorded demo of how the game is meant to function. This demo has a few explanatory prompts, but it also has long, unexplained pauses, perhaps meant for a live demonstration by MBS staffers to interested Chevron managers.

Since many of the on-screen buttons don't function properly and the disk doesn't include anything in the way of instructions or documentation, understanding exactly what works in this incomplete build of SimRefinery is still quite vague. For now, we know that you can use the game's menus to mix "recipes" that include potentially explosive compounds like C4 and MTBE. A peek at Salvador's Twitch stream of the game revealed at least one apparent fire, along with calamities like "regenerator upsets," which he created with help from his most engineering-minded chat members. So, yes, chaos is certainly possible within this incomplete version of SimRefinery, which Salvador's article would remind you was a major point of the software: "If you start breaking the refinery, you can see how ruining one part of the plant will affect the other parts of the plant," he wrote. We heartily invite all of you to fiddle with the prototype and cause as much intentional—and absolutely educational—refinery destruction as possible.

Promoted Comments

Landak Wise, Aged Ars Veteran et Subscriptor

JUMP TO POSTI won't comment on how accurate the game is, but I can at least explain some of the terms. I'm essentially certain that large plants have software a bit like this (but clearly less fun...) already running, and have done for a long time. The oil and gas industry are very much aware that maths, physics, software engineering, and generally speaking, being smart, results in a competitive advantage. As you know, the basic idea behind an oil refinery is to turn a complex mix of hydrocarbons of varying molecular weights (and impurities, like sulphur) into well-defined fractions separated out by molecular weight and molecular properties. Typically as some of these are a /lot/ more valuable than others, we can Do Chemistry™ to convert cheaper, more plentiful fractions into rarer, more valuable ones, if market conditions prevail. My guess is that all of the buttons on the left are presumably interfaces for buildings that work on a particular range of molecular weights, starting with light gasses (C2-C4) and ending up with asphalt. A brief glossary of random terms, with the disclaimer that I am not a petrochemist (but have a PhD essentially in physical chemistry): FCC Unit: Fluid catalytic cracking unit; this converts, in the liquid state, with a catalyst, high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils into more valuable gasoline, olefinic gases, and other products. This is one of many ways in which BigOil makes its money. A friendly schematic is below, details here: Spoiler: show And a slightly more complete schematic:Spoiler: show Jet: Kerosene or jet fuel, typically C6 to C16 in length (actual jet fuel is certified and guaranteed to a high degree and a blend known as Jet-A1 is the internationally used standard one (C8 to C16 with a freezing point of -47ºC)) Alkylation: the transfer of an alkyl group from one molecule to another, i.e. moving C's around for $'s. There are many different ways of doing this, mostly involving compounds like HF (an acid that literally eats your bones if you spill it on your hands, and will go through nitrile gloves (unpleasant link – the white stuff is the calcium originally in bone)) or, on the small-scale in an organic chemistry lab, a deprotonating agent like tert-butyl-lithium (BuLi) which spontaneously ignites on contact with air and makes a pretty cool flamethrower (you might only see it once). The most common process is probably the acid alkylation, usually with HF, sometimes with H2SO4, sometimes with a solid catalyst. As before, a brief flow diagram below, details hereSpoiler: show Hydrocracker: cracking (i.e. splitting longer carbon molecules to smaller ones) with subsequent hydrogenation (i.e. saturating C=C to C-C) using high pressure, high temperature, a catalyst, and hydrogen. This is a complex process that, if it goes wrong, can go very wrong -- think "insane fireball" wrong. A schematic is below, and a good primer is here: Spoiler: show Jet/diesel hydrofiner -- fining is removing sulphur from fuels (and hence reducing acid rain), hydrogenation is the 'hydro' in that; put the two together and you get better gasoline at once. Also called 'hydrodesulpherisation'. Produces hydrogen sulphide (H2S) as a by-product. Note that hydrogen sulphide is another one of those lovely compounds that (a) smells of rotten eggs, until its concentration gets so high where it (b) kills your nasal endothelium and sense of smell, before (c) killing you. A typical oil refinery would produce many tons of these [greenhouse] gasses on a very regular basis, and the resulting "sour" gas is then "sweetened", with an amine process ultimately producing CO2 and neat H2S which is then converted via the Claus process to elemental sulphur and water. Schematic below, overview here.Spoiler: show LSR: This is a type of naptha; light gas (~C5) and is typically 'cut' into part of a gasoline mixture as a low octane rating, low vapour-pressure fuel source or it is used in steam crackers to make ethylene and ultimately make plastics. LGO: Light gas oil -- a heavy crude fraction (C8–C15 hydrocarbons with a distillation range of 150–275 °C) HGO: Heavy gas oil -- a heavier crude fraction (C11–C24 hydrocarbons with a distillation range of 190–350 °C) Residium: Unsurprisingly, the residue from crude oil after distilling off all but the heaviest components (C>70), with a boiling range greater than 550 ºC. Typically either processed (cracked) with more difficulty, or turned into bitumen. iC4: Isobutane. Behaves slightly differently to ordinary butane and is often industrially higher in demand; isomerisation units will convert the two if (economically) required. H2: Hydrogen -- often created in order to be used for saturating C=C in a large oil refinery; byproduct of many reactions, desirable for many reactions. Famously goes boom loudly and hard to contain. It's therefore typically one of many gasses burnt at a flue on the site. There's also a story here about helium extraction, which is mostly done at refineries and/or oil wells as it is the lightest gas, has a mean velocity greater than escape velocity of earth, and constantly leaves the atmosphere. Some refineries have gas centrifuges and try to extract it out of flue gas, but the economic value of that is usually marginal at best. OTPC: Once-through partial conversion [of heavy gas oils / undesirable products into gasoline mixtures, with a relatively shot-gun approach; compare with 'total conversion'] Catalytic reformer: converting low-octane napthas into higher octane liquid reformates, that then get blended into petrol / gasoline. This is basically converting low-octane linear hydrocarbons (paraffins) into branched alkanes (isoparaffins) and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons. The dehydrogenation also produces significant amounts of byproduct hydrogen gas, fed into the hydrocracker above. As before, schematic below, details here.Spoiler: show Reformate: see above. FCC gasoline: this is is the primary product of the FCC unit (see above) Lubricating oil: typically C20-50, used for lubrication but not necessarily anything like the demand as higher fractions, and thus typically cracked Fuel oil: the absolute cruddiest, longest oil that is commonly used; typically C20-70 and vast amounts go into (highly polluting) international shipping. Gasoline/Petrol: Typically C5-10, with a complex mix of several hundred to thousand individual molecules. A highly engineered product, modern production is tightly regulated and has many important, competing considerations. Also clearly terrible for the planet in the amounts we consume it.

Diesel: another highly engineered product fuel, C9-C20, distinguished from the gas oil (diesel oil) fraction of C14-C20 that comes out. BPOD: fuel flow rate (in barrels) per operational day. One barrel is ~159 litres, 35 imperial gallons, or 42 US gallons. A typical refinery will be able to churn through ~100k barrels per day of crude (though that number varies hugely). MTBE: Methyl-tertiarybutyl-ether -- a common blend stock into gasoline that, like most of these compounds, is not what you would like to go smoking near. While this one is a more de facto explosive, the "C4" referred to in the article isn't C-4 the plastic explosive; it's butane. I think that's most of them -- any requests and I'll edit this to include them. Also, all images are public domain, mostly from Wikipedia.




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