Know-how for Ethanolamine Production

Sulzer Chemtech has more than 25 years’ experience in CHRISTOPH BRODMANN the field of ethanolamine technology. This know-how URS HALLER enables offers to be made for comprehensive engineering ARVID K. ELDRING services as well as key components, such as distillation SULZER CHEMTECH packings, and for the modernization of existing . Sulzer Chemtech has been supplying complete plants for the production of ethanolamine for some years.

The distillation technology 1 The first complete from Sulzer for ethanolamines, especial- Chemtech for ethanolamine production has ly structured packings, for the been operating in Fushun (NE China) since majority of the plants worldwide 1997. The second is also located in NE China, and the most important producers the third is under construction in Taiwan. emanates from Sulzer Chemtech. The first Sulzer packings were installed more than 25 years ago, and since then Sulzer Chemtech has continuously extended its spectrum of products in the field of ethanolamine technology. For example, existing columns can also

32 SULZER TECHNICAL REVIEW 2/2000 3937 2 To guarantee values in the production, e.g. for purity and capacity, as a minimum, Sulzer Chemtech supplies diverse key components such as distillation packings (a), heat exchangers (b, ellipse), mixers for the reaction (c), and also the control system (d).

0682 2018 a b be retrofitted now with Sulzer c d packings. Complete plants (sys- tems) have also been supplied for some years (Fig. 1). As a mini- mum, Sulzer Chemtech provides the basic engineering, key compo- nents (Fig. 2), as well as the licence for the distillation technol- ogy. Sulzer Chemtech acquired the services of the Italian company Conser S.p.A., the licensor for the reaction, with which it first be- came possible to offer complete plants. Beside the structured pack- ing (Mellapak), the key compo- steam-trace heating to ensure that neering and contract-processing nents include the heat exchangers the do not solidify at the departments handle the contract and the vacuum system for the very low temperatures (down to together. This maximizes the cus- columns, the mixers for the reac- –20 °C). tomer benefits. tion, as well as the complete plant One of the plants produces 10 000 t control system. The supply of the ethanolamine a year, the other RANGE OF APPLICATION key components enables Sulzer 5000 t. Sulzer Chemtech is now FOR ETHANOLAMINES Chemtech to guarantee the reli- extending the first plant with a Irrespective of whether it is need- able operation. Furthermore, im- second production line, which will ed for gas purification or raw mate- portant parameters such as pro- double the output capacity. rial for the synthesis of fine chemi- duction purity and the capacity of A third complete plant from Sulzer cals, the range of application for the plant comply with the respec- Chemtech is being under construc- enthanolamines is very diverse tive specifications. tion in Kaohsiung (Taiwan) and (Fig. 3). The mostly utilized fea- will be commissioned in the second ture of ethanolamines is the sur- THIRD COMPLETE PLANT half of this year. In this case, face tension reducing effect, which UNDER CONSTRUCTION Sulzer Chemtech is not only re- enables the mixing of water-solu- Two complete plants from Sulzer sponsible for the engineering, but ble and water-insoluble sub- Chemtech are already in opera- also for the commissioning. The stances. There are three different tion; both are located in NE China. Oriental Union Chemical Corpora- ethanolamines: mono-, di- and The guaranteed values for the tion wants to produce 40 000 t/a triethanol. Monoethanolamine is product purity, colour (quality in this plant. Further proj- used primarily for the extraction of characteristic) and capacity have ects are being processed. CO2 and H2S from natural gas. been attained. Since the climatic So-called product teams, compris- is employed, first conditions which prevail in this ing various experts and product and foremost, for organic synthe- part of China during the winter departments, are formed for the sis. 85% serves warrant special consideration, the project development: One person among others as an additive in the plants have to be provided with each from the sales, process engi- cement industry.

SULZER TECHNICAL REVIEW 2/2000 33 © Photodisc

b © Photodisc c d

a 3 Principal area of application for ethanolamines is the e © Photodisc gas purification process, by which CO2 and H2S are extracted from natural gas (a). © Photodisc In addition, they are also employed as raw material, e.g. for © Photodisc must be taken that its conversion the more yellow the ethanolamines pesticides (b), toilet is complete. Alternative processes become. The colour, however, is the requisites (shaving operate with highly concentrated most important quality character- foam, c) or detergents At the moment, the world market . Since pure ammonia is istic; the colourless the substances (d), as well as an for all three enthanolamines is gaseous under normal conditions, are, the higher the market value. additive in the cement about 1 mio. t/a, whereby approxi- it is necessary to work under high After the reaction, the surplus industry (e). mately 50% is sold in the USA and pressure (50–70 bar) with this ammonia is stripped out and the Western Europe. The most impor- process. water removed from the reaction tant producers are located in the The formation of mono-, di- or tri- mixture by distillation. Both are USA, Europe and Japan. The ethanolamine depends thereby on returned to the reaction again. worldwide growth rate is estimat- whether an ammonia molecule After this, the ethanolamines are ed to be 3–4% per annum, and it is reacts with one, two or three ethyl- separated from each other in probably as much as 6–8% in the ene oxide molecules. The composi- a three-step distillation unit. non-producing Asian countries. tion of the resulted mixture Thanks to the low pressure losses, Many of these countries plan to depends on the ratio of the raw for which the structured packings manufacture ethanolamine them- materials and can be varied in a from Sulzer Chemtech are selves in future to cover their own goal-oriented manner. The higher renowned, it is possible to perform requirements. the proportion of ammonia, the the distillations at very low pres- more monoethanolamine is formed sures (head pressure 2 mbar) and FEW BY-PRODUCTS AND – with the Sulzer Chemtech therefore also at low temperatures. HIGH FLEXIBILITY process it is a maximum of 70%. The ring-vacuum pumps The raw materials for the reaction from Sulzer Burckhardt also con- are ammonia/water and ethylene HIGH QUALITY THANKS tribute to the gentle distillation, oxide (Fig. 4). The reaction takes TO LOW TEMPERATURES because their reliable and stable place without catalyst and is sig- One of the major difficulties is the operation keep constant pressure nificantly exothermic, i.e., the de- separation of the products, be- in the column. In addition, so- veloped heat has to be removed cause ethanolamines are sensitive called falling-film evaporators are continuously. Due to the high reac- to heat and they have to be sepa- applied to vaporize the bottom tivity of (among oth- rated with every care. The higher product with the utmost care ers the danger of explosion), care the temperature (the pressure), again.

34 SULZER TECHNICAL REVIEW 2/2000 ECOLOGY-FRIENDLY This process may be rightfully can, together with a partner, offer PROCESS described as ecology-friendly. the technology for the production A purity of more than 99% is of brake fluids. At the moment, the attained with all three products. FURTHER TECHNOLOGIES worldwide demand for glycol ether Technical grade triethanolamine In addition to the ethanolamine is about 750 000 t/a. Ω with a purity of 85% is obtained as technology, Sulzer Chemtech offers a residual product of the distilla- together with customers and part- tion, which is also a valuable prod- ners further technologies for reac- uct. In other words, there are no tion and separation, for instance FOR MORE DETAILS organic waste products throughout the purification of ethylene oxide Sulzer Chemtech AG the complete process and only 0.1% as well as the technology and the Urs Haller of the used water has to be dis- key components for ethylene gly- Postfach 65 posed as waste water. Thanks to cols, alkylethanolamines and gly- CH-8404 Winterthur the high separation efficiency of col ethers. Glycol ethers (reaction Switzerland the packings, the energy consump- of ethylene oxide with ) are Telephone +41 (0)52-262 37 98 tion of the columns is low and employed as solvents for paints or Fax +41 (0)52-262 00 76 smaller columns can be employed. for brake fluids. Sulzer Chemtech E-mail [email protected]

4 A mixture is formed from the three kinds of ethanolamine (mono-, di- and tri- ethanolamine) by means of a non-cat- alytic reaction and is then separated by Ammonia Reaction Ammonia Amine solution Amines Distillation absorption stripping Dehydration Monoethanol- means of distillation. Raw material storage amine Ethylene Ammonia Diethanol- Ammonia oxide amine Triethanol- amine

Water

Waste water Triethanolamine technical grade (85%)

SULZER TECHNICAL REVIEW 2/2000 35