science

Union process

Union process is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Union process rather than just read about it. In short: The Union process was an above ground shale oil extraction technology for production of shale oil, a type of synthetic crude oil. The process used a vertical retort where heating causes decomposition of oil shale into shale oil, oil shale gas and spent residue.

Key takeaways

Union process belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Union process to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Union process from memory before moving on to harder problems.

Reference excerpt

The Union process was an above ground shale oil extraction technology for production of shale oil, a type of synthetic crude oil. The process used a vertical retort where heating causes decomposition of oil shale into shale oil, oil shale gas and spent residue. The particularity of this process is that oil shale in the retort moves from the bottom upward to the top, countercurrent to the descending hot gases, by a mechanism known as a rock pump. The process technology was invented by the American oil company Unocal Corporation in late 1940s and was developed through several decades. The largest oil shale retort ever built was the Union B type retort.

History Union Oil Company of California (Unocal) started its oil shale activities in 1920s. In 1921, it acquired an oil shale tract in the Parachute Creek area of Colorado, southern Piceance Basin. The development of the Union process began in the late 1940s, when the Union A retort was designed. This technology was tested between 1954 and 1958 at the company-owned tract in the Parachute Creek. During these tests, up to 1,200 tonne per day of oil shale was processed, resulting of 800 barrels per day (130 m3/d) shale oil, which was refined at a Colorado refinery. More than 13,000 barrels (2,100 m3) of gasoline and fuels were produced. This production was finally shut down in 1961 due to cost. In 1974, the Union B process, evolved from the Union A process, was developed. In 1976, Union announced its plans to build a Union B demonstration plant. Construction started in 1981 at Long Ridge in Garfield County, Colorado, and the plant was started its operations in 1986. It was closed in 1991 after production of 5 million barrels (790×10^3 m3) shale oil.

Process The Union process can be operated in two different combustion modes, which are direct and indirect. The Union A (direct) process is similar to the gas combustion retort technology, classified as an internal combustion method, while the Union B (indirect) process is classified as an externally generated hot gas method. The Union retort is a vertical shaft retort. The main difference to other vertical shaft retorts such as Kiviter, Petrosix, Paraho and Fushun is that crushed oil shale is fed through the bottom of the retort rather than the top. Lumps of oil shale in size of 3.2 to 50.8 millimetres (0.13 to 2.00 in) are moved upwards through the retort by a solids pump (known as a "rock pump"). Hot gases, generated by internal combustion or circulated through the top of the retort, decompose the oil shale while descending. The pyrolysis occurs at the temperature of 510 °C (950.0 °F) to 540 °C (1,004.0 °F). Condensed shale oil and gases are removed from the retort at the bottom. Part of the gases is recirculated for pyrolysis and fueling combustion, while other part could be used as product gas. The spent shale is removed from the top of the retort. After cooling with a water, it is conveyed to the waste disposal.

Advantages The Union retort design has several advantages. The reducing atmosphere in the retort allows the removal of sulfur and nitrogen compounds through the formation of hydrogen sulfide and ammonia. Oil vapors are cooled by the raw oil, thus minimizing polymer formation among the hydrocarbon fractions.

See also Alberta Taciuk Process Galoter process Fushun process Kiviter process Lurgi-Ruhrgas process Paraho process Petrosix TOSCO II process Superior multimineral process

References

Worked examples

Example 1 — a first encounter with Union process

Start with the simplest possible case. Write down what Union process claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Union process before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Union process ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Union process

In research: Union process appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Union process in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Union process is common in secondary-school and first-year university syllabi. It links to neighbouring topics Oil shale technology, so understanding it makes those chapters shorter.
In everyday life: Look for Union process outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Union process in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Union process means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Union process out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Union process in simple terms?

Why does Union process matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Union process?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Union process.