Page 478 - Compression Machinery for Oil and Gas

458 SECTION III Applications

FIG. 12.4 Picture of reciprocating compressor OEM test stand. (Courtesy of Ariel Corporation.)

Reciprocating Compressors

A no-load mechanical run test performed at the factory is very common for
reciprocating compressors used in the oil and gas industry. Fig. 12.4 provides
a picture of a test stand for factory acceptance testing. Manufacturers will gen-
erally follow API Standard 618 [6] requirements, which specify a 4-h no-load
run test according to the manufacturer’s standard procedure (reference API 618
[6] Fifth Edition, paragraph 8.3.3). A “no-load test” means no gas is compressed
and, at a minimum, no suction compressor valves are installed in the cylinders.
Some manufacturers will install the discharge valves prior to the test.
The purpose of the no-load mechanical run test is to ensure that the machine
is mechanically sound and the two lubrication systems, one for the frame run-
ning gear and the other for the cylinder bore and piston rod packing, are func-
tioning properly.
A typical procedure will have the compressor driven by a variable speed
electric motor and will begin the test at some reduced speed, typically about
50% of full rated speed. Over the span of the 4-h test, the speed will be incre-
mentally increased with the last increment being the full rated speed for that
compressor.
During the test, several parameters such as rotating speed and frame oil pres-
sure and temperature are checked and recorded. If the unit is equipped with
main bearing, temperature-sensing devices this output will also be recorded.