Chemical industry
Hydrogen fluoride
( HF ) is a very useful chemical compound which finds widespread application in laboratories , manufacturing facilities as well as large-scale industrial processes such as alkylation . Unfortunately , HF is at the same time an extremely hazardous substance , meaning that all process equipment needs to be designed and built to the highest of standards . Valve World reviewed the production , usage and handling of HF , and checked out how manufacturers engineer valves suited for HF alkylation units .
HF – treat it with the utmost respect
By KCI Editorial
Description
Pure hydrogen fluoride ( HF ) has a boiling point around 20 ° C ( 67 ° F ). It therefore exists as a liquid at low temperatures , converting into a gas at about the standard room temperature . HF readily dissolves in water , creating hydrofluoric acid . Standard hydrofluoric acid commercial concentrations are around 50 %, although stronger solutions ( 70 %) are also available . Both hydrogen fluoride as well as hydrofluoric acid are highly corrosive . From the chemical perspective there are differences between hydrogen fluoride and hydrofluoric acid . However , for practical purposes they are considered to be the same substance . This article will henceforth use the general term HF .
Uses
HF finds widespread use in a myriad of applications . The pharmaceutical sector for example uses it to help produce fluoxetine , which is better known as the antidepressant Prozac . HF is also used in the production of polytetrafluoroethylene , more familiar to cooks around the world as PTFE , found in non-stick frying pans . In industrial applications , HF is widely used to etch glass and silicon wafers as well as metal extraction and stainless steel picking . HF is furthermore used in the production of refrigerants , herbicides , phosphate fertilisers , pharmaceuticals , aluminium , plastics , electrical components and fluorescent light bulbs . And , coming right up to date , HF is also used in chemical lasers .
HSE
Whilst HF is present in the air ( from natural and industrial sources ), the levels are low and not expected to cause adverse health effects . Incidents involving HF exposure are therefore typically associated with occupational settings . This could include breathing in the fumes or skin contact . Depending on the concentration , skin contact with HF can cause severe and painful burning . Note that burns on the skin may not be visible until 24 hours after exposure . Breathing in HF can irritate the eyes and nose , cause a sore throat , as well as coughing , headaches and confusion . Exposure to high levels of HF can lead to drowsiness and heart problems . Ingestion of just a small quantity of highly concentrated HF will affect major internal organs and may be fatal . Given the above , authorities typically draw up guidelines to protect worker safety . These include good working practices , hazard assessments and suitable personal protective equipment ( PPE ). For example , a long-sleeved shirt , long trousers , and closed shoes are recommended even when working with small quantities of dilute forms of HF . As the risks become more significant – such as from potential exposure to higher HF concentrations – then the use of protective goggles and a face shield are often mandatory . An HF-resistant full-body apron and chemicalresistant boots are recommended if there is a risk of splashing .
HF in refining
Concentrated HF is widely found in refineries , where it serves as a catalyst in the alkylation process ( alkylation helps to boost octane level ). Despite requiring tighter safety protocols , HF is often preferred to the alternative catalyst , sulphuric acid , as ( i ) the same output can be achieved with far less acid ( ii ) by-products are minimal and ( iii ) a wider range of feedstocks can be processed . Note that for various reasons , alkylation plants are often ‘ split ’ into two separate areas , termed acidic and non-acidic .
Market projections
Data research companies offer positive yet varied perspectives on the size and growth in demand for HF valves for alkylation . One suggests that the market value for all HF valves combined will
14 Valve World February 2025 www . valve-world . net