KRAL F Series Biofuel and Methanol Pump

The KRAL F-series biofuel pump is a triple-screw pump designed for alternative fuels: biodiesel, methanol, ammonia, ethanol, HVO and FAME. The manufacturer is KRAL, Austria, and it positions the series specifically as a pump for the fuels of the future. The housing and all parts in contact with the fluid are made of stainless steel, whilst the drive consists of a sealed magnetic coupling as standard.

For which fuels is the F series designed?

The manufacturer specifically lists the following media: biofuels, methanol, ammonia, ethanol, HVO and FAME. It is specifically noted that the pump is suitable for fuels with an acid number exceeding 0.5 mg KOH/g — it is precisely this acidity that makes alternative fuels problematic for conventional cast-iron pumps.

The second challenge is viscosity. Methanol and ammonia have virtually no lubricating properties, and the F series is designed to operate at 0.2 mm²/s or higher, which is lower than that of diesel fuel.

Why are stainless steel and magnetic couplings the standard here?

Acidic and corrosive fuels corrode cast iron, which is why the housing, screws and the entire flow path are made of stainless steel; the screws also have increased surface hardness and special coatings.

Methanol and ammonia are toxic and volatile, so a leak is unacceptable under any circumstances. There is no mechanical seal here — the torque is transmitted via a sealed magnetic clutch, and in the F series, this is not an option but comes as standard.

Technical Specifications of the KRAL F Series

Size	Flow rate (2,900 min⁻¹, 40 bar, 1 mm²/s)
15-20	up to 25 l/min
32-42	up to 60 l/min
55-74-85	up to 120 l/min
105-118	up to 180 litres per minute

Parameter	Value
Type	three-screw pump, hermetically sealed design
Max. differential pressure	120 bar
Max. supply pressure	16 bar
Max. temperature	80 °C
Viscosity	from 0.2 mm²/s
Max. revs	4,000 min⁻¹
Material of the housing and wetted parts	stainless steel (as standard)
Screws	stainless steel, increased surface hardness, special coatings
Drive	magnetic clutch (as standard)
Explosion protection	ATEX, Zones 1 and 2

The differential pressure depends on the fuel

The overall limit for the series is 120 bar, but the manufacturer specifies individual values for specific media:

Environment	Differential pressure
Light fuel oil (LFO), biofuels	up to 80 bar
Methanol, ammonia	up to 30 bar

This is not a safety margin, but an operational limit — it must be factored into the circuit calculations as early as the design stage.

Implementation

The manufacturer offers three versions: a flanged pump with an axial inlet, a flanged pump with a radial inlet, and a vertical pump mounted on a stand. The choice depends on the installation configuration: the vertical version is used for mounting on a tank, whilst the flanged versions are used for integration into a pipeline.

Where are F-series pumps used?

For conventional petroleum products with standard lubricating properties, cheaper solutions are provided by KRAL K Series, for harsh and contaminated environments — KRAL Z Series.

Selection and service from Steiner Ukraine

The F-series pump is selected based on the fuel: first, the specific medium and its acid number are determined; next, the required differential pressure is established, taking into account the limitations for methanol and ammonia; and only then is the model size selected based on flow rate and design requirements. We coordinate the configuration with the manufacturer and ensure service and spare parts. Steiner Ukraine has been operating in the industrial equipment market since 2006.