Not a teacher.
(Although / In spite of) being a latecomer, the company has grown remarkably since its foundation, and finally has become the most profitable oil refinder in the country.
I understand "In spite of"is right, but I wonder if "Although" is also possible, considering as the articipial construction.
"Although the company was a latecomer, ~" -> "(Although) being a latecomer, ~" like this.
Or how about this case? "In spite of a latecomer, ~"
Sometimes I'm confused with distinguishing the preposition and the conjunction accurately.
Please explain to me.
Not a teacher.
Your confusion is understandable: even some otherwise respectworthy grammarians seem to have difficulty at times distinguishing between prepositions and subordinating conjunctions!
In common with most subordinators, however, 'although' has the facility to be followed by an elliptical clause from which subject and verb have been removed, leaving only the complement. Thus, just as we can abbreviate
When he was happy, he was very happy, but when he was sad, he was very sad.
When happy, he was very happy, but when sad, he was very sad.
we can abbreviate
Although he was rich, he was not happy.
Although rich, he was not happy.
The remaining complement is often a participle, but for the sentence to be acceptable/meaningful, it must similarly be possible to reconstitute the original full clause whilst retaining the participle unchanged. Thus
While working in the fields, they laughed and sang.
is an ellipsis of
While they were working in the fields, they laughed and sang.
Although supposedly studying, he was actually daydreaming.
is elliptical for
Although he was supposedly studying, he was actually daydreaming.
However, comparing the above with an ostensibly similar but structurally quite different sentence containing a preposition (despite) governing a gerund (studying), e.g.
Despite studying, he failed to pass a single test.
(meaning: Although he studied, he failed to pass...)
it should become clear why 'although' cannot - meaningfully - be substituted here, since a sentence
?Although studying, he failed to pass a single test.
could represent only semantically somewhat bizarre
?Although he was studying, he failed to pass...
Thus the issue of whether to follow 'although' with an -ing form is primarily one of sense rather than of syntax!