Formic acid production facilities

Formic acid — the first in the number of saturated monocarboxylic acids. Widely used in pharmaceutical, pulp, cosmetics and food industries, agriculture, fine organic synthesis, leather and textile factories, in the production of metal formate and pentaerythritol.

Formic acid consumption market by application in 2011 is as follows:

Almost 45% of the total formic acid demand was for the silage preservation, animal feed, and other agriculture applications in 2012, with the leather & textile and rubber industry also being the fastest growing end-use segments, primarily due to high penetration of leather and textiles in all the regions.

The formic acid market is experiencing enormous growth. Bringing up to date the consumption of formic acid (FA) in Russia is estimated at about 3000 — 4000 thousand tons per year and grows steadily. Despite such high demand, the production of formic acid in Russia is practically absent.

Two major industrial technologies for formic acid production:

These multi-stage liquid-phase processes have the number of disadvantages: significant capital intensity and energy-intensive stages of production, as well as a generation of large amount of wastewater and by-products.

Specialists of Safe Technologies Inc. together with the Institute of Catalysis named after Boreskov of Siberian Branch of the Russian Academy of Sciences was developed a new gas-phase process for the synthesis of formic acid by direct oxidation of formaldehyde on a specially selected catalyst. Methanol was used as a source of formaldehyde production:

Thus, the developed method for formic acid production from methanol as follows:

Gas-phase catalytic technology process description for the synthesis of formic acid from methanol

1. Methanol-air mixture production:

Methanol is pumped into the air stream driven by blower, methanol-air mixture is preheated in a recuperative heat-exchanger by the heat of formaldehyde-containing gas from the reactor.

2. Methanol oxidation:

At this stage, the oxidation of methanol to formaldehyde in the reactor is carried out in accordance with customized and patented technology on iron-molybdenum catalyst. The yield at this stage reaches 92-94%. Further, the formaldehyde gas is fed to the recuperative heat exchanger where it is cooled by mixture of methanol and air, and then is directed to the next oxidation step.

3. Methanol oxidation reactor cooling:

The heat of the methanol oxidation reaction can be used further efficiently. Heat extraction is carried out by high boiling organic coolant — diphenyl mixture. It is condensed to the steam, which comes through the separator to the enterprise network.

Vent gas from shell side of the condenser is cleaned on carbon filter before being discharged into the atmosphere. Purification rates exceed 99%.

4. Formaldehyde oxidation

Cooled vapor and gas mixture consisting of formaldehyde, water and air is directed to the reactor, loaded with a specially developed and patented oxide catalyst. Formaldehyde is oxidized in the reactor at a temperature of 100 to 130°C to the formic acid. The yield of this reaction is 85%.  The heat of reaction is removed by boiling water entering the shell side of the reactor.

5. Vapor condensation and formic acid production

The reaction mixture contained vapors of formic acid and water, as well as nitrogen, carbon monoxide and oxygen is supplied to the two-stage countercurrent condenser which is cooled by circulating water and antifreeze. After passing through the separator, resulted formic acid with a concentration of 55 — 60% is supplied to the receiver tank. The plant can be accompanied by rectification unit to obtain a product with a concentration up to 85%.

6. Catalytic conversion of gas emissions

Released from formic acid gases after product separator are directed to catalytic converter where at the temperature 400-500°C. Purification rates exceed 98%.

Advantages of the new formic acid production technology:

1. Process flow simplicity with minimum number of technological steps
2. Low capital investment
3. Low cost of the final product
4. Environmental safety of production:

•  All emissions from the process are purified at special gas cleaning system;
• The technological process allows avoiding contamination of sewage;
• Full environmental safety can significantly reduce the sanitary protection zone.

5. High quality of the product produced:

• Automatic dosing of methanol and air;
• Control of temperature by height of the catalyst layer in three devices (32 points) and pressure (8 points);
• Chromatographic analysis of the reaction products in three detectors.

6. Small plant size.

7. The process worked out on an automated installation at the Institute of Catalysis named after Boreskov of Siberian Branch of the Russian Academy of Sciences, plant capacity by methanol is up to 3 kg/h.