Sulfonation reactor

After the SO converter has stabilized, the 6—7% SO gas stream can be further diluted with dry air, I, to provide the SO reaction gas at a prescribed concentration, ca 4 vol % for LAB sulfonation and ca 2.5% for alcohol ethoxylate sulfation. The molten sulfur is accurately measured and controlled by mass flow meters. The organic feedstock is also accurately controlled by mass flow meters and a variable speed-driven gear pump. The high velocity SO reaction gas and organic feedstock are introduced into the top of the sulfonation reactor,, in cocurrent downward flow where the reaction product and gas are separated in a cyclone separator, K, then pumped to a cooler, L, and circulated back into a quench cooling reservoir at the base of the reactor, unique to Chemithon concentric reactor systems. The gas stream from the cyclone separator, M, is sent to an electrostatic precipitator (ESP), N, which removes entrained acidic organics, and then sent to the packed tower, H, where SO2 and any SO traces are adsorbed in a dilute NaOH solution and finally vented, O. Even a 99% conversion of SO2 to SO contributes ca 500 ppm SO2 to the effluent gas. 

There are four main sulfonation reactor configurations applied worldwide to produce all kinds of top quality anionic surfactants from sulfur-based S03/air as the sulfonating agent. All these systems have proven and documented experience ... 

Only the Ballestra MTFFR will be described as an example of a modern sulfonation reactor configuration. The process consists of the following units ... 

Neutralization of organic acid within 1 min after sulfonation reactor. A separate aging step is not needed under commercial reactor conditions Short residence time falling film reactor required to avoid thermal breakdown of R0S03H... 

Notes All water cooled exchangers operate with water in at 75°F and out at 100°F. All pumps are centrifugal except the complex transfer, and the sulfonation reactor feed, which are both piston type the neutralization reactor recirculation pump and the transfer pumps are gear pumps. 

The use of oleum (H2S04 S03) for maintaining the necessary sulfur trioxide concentration of a sulfonation mixture is a practical procedure. Preferably the oleum and organic compound should be added gradually and concurrently to a large volume of cycle acid so as to take up the water as rapidly as it is formed by the reaction. Sulfur trioxide may be added intermittently to the sulfonation reactor to maintain the sulfur trioxide concentration above the value for the desired degree of sulfonation. 

Ballestra S.P.A., Italy has suggested that the process of making sodium toluene sulfonate can be improved by removing water formed from the sulfonation reactors by azeotropic distillation of water-toluene mixture along with excess of toluene required (necessary to form the proper mole ratio of water/toluene). Toluene along with water is condensed as an azeotrope from the distillation column and then recovered toluene is recycled back to the sulfonators. By using this process, less of toluene and H2SO4 will be required for the process of sulfonation. 

In Example 10.3.1 we considered the calculation of the mass transfer coefficient in the gas phase of a thin-film sulfonator. A schematic diagram of a sulfonation reactor was provided by Figure 10.5. Now, in the modeling of the reactor, the estimation of the temperature profiles along the reactor tube is very important. An important parameter in the determination of the temperature profiles is the gas-phase heat transfer coefficient. Estimate this heat transfer coefficient at the entrance to the reactor for the same set of operating conditions as specified in Example 10.3.1. 

Since the heat capacity of SO3 is very high there is a substantial correction to the heat transfer coefficient caused by simultaneous mass transfer. Simultaneous mass and energy transfer needs to be properly taken into consideration in the design of industrial thin-film sulfonation reactors. ... 

Mist separator 2 Falling-film sulfonation reactor 3 Gas separator 4 Finishing reactor 5 Hydrolyser 6 Blender 7 Storage tank... 

Sulfonation reactor 2 Nitration reactor 3 NOx-separation 4 Neutralizing vessel 5 Filtration vessel 6 Reduction reactor 7 Precipitation vessel 8 Tri-Na-salt formation 9 Concentration vessel 10 Melt reactor 11 Precipitation vessel... 

FIGURE 1.13 Ballestramultitube film sulfonation reactor. (From Ballestra, S.P.A., 2005. With permission.)... 

The control over the LAB-SO3 reaction is totally dependent on the design approach adopted for the reactor where the two reactants are contacted therefore, the sulfonation reactor is indeed the heart of a sulfonation plant and its concept should be based on the deepest possible knowledge on what exactly takes place when LAB and gaseous SO3 react. 

The cascade-type sulfonation reactors [6] have been adopted in a large number of plants and considered as the state-of-the-art reactors until the mid-1970s, when new reactors based on the principle of the falling film were introduced [7]. 

In the frame of the sulfonation plant for LAS production, the exhaust gas leaving the sulfonation reactor (-1.8 to 2.0 kg/kg of processed LAB) contains a pollutant load of a few thousand parts per million mainly constituted by SO2 (derived by the incomplete conversion of SOj to SO3), unreacted SO3, and organic mist composed of partially suUbnated material physically entrained by the gas. 

An example of the flexibility of the preceding sulfonation technology making use of gaseous SO3 and film sulfonation reactor is represented by the production of a-olefin sulfonates (AOS). 

A detailed description of typical sulfonation systems - is omitted from the production descriptions contained in this chapter. However, all MES processes share the common use of a falling-film sulfonation system for the initial reaction of ME with air/SOj. The processes differ in the treatment of MESA after the sulfonation reactor. The sulfonation systems shown in Figure 11.1 are generic for... 

Johnson, G. and Oxynes, B.L. Modeling of a Thin Film Sulfur Trioxide Sulfonization Reactor. Ind. Eng. Chem. Process Des. Develop, 13(1), 6-14, 1974. 

Chlorosulfonic Acid — Ethyl Ether System - 32 0 - E - S sulfonation reactor, 20 hrs. 

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