Liquid or solid sulfur goes into pipelines insulated by steam coil and jacket, then introduced to the sulfur melting tank, afterwards pumped to the high-level tank and continues transfer to the sulfur burner by submerged gear pump or gear pump insulated by the steam jacket. By adopting the mass-flow meter and VFD of the gear pump, the flow of liquid sulfur is controlled at a stable rate.     Features: WEIXIAN liquid sulfur gear pump won't be blocked by impurities and the flow rate of liquid sulfur is controlled by the mass flow meter and VFD, so the flow is stable and accurate; also achieves online operation parameters readable, which provides the best convenience for controlling SO3 concentration, plant performance adjustment and products switching.

The air from the atmosphere is compressed by the main blower and transferred to a dehumidifier, then remove most moisture by water cooling and chilling, after then the air goes to silica gel for deep de-humidification, and finally gets dry air with dew point of -60℃. The flow rate of dry air (Nm3/h or kg/h) is controlled by the speed of the main blower (through the orifice flow meter and main blower VFD).   Features: The air cooling fin type heat exchanger uses SS304 as the fin plate and tube, the working life is much longer than the copper tube and aluminum plate. 

Liquid sulfur goes to the sulfur burner by precise measurement and fully combusts with dry air to generate SO₂; after cooling, SO₂ gas goes to the converter and convert to SO₃ by vanadium catalyst. After cooling, SO₃ gas goes to sulphonation/sulfation unit; SO₂ and SO₃ gas are cooled by cooling air through tube type heat exchanger; after heat exchanging, the hot air generated in this process is collected and goes to waste heat recovery unit to produce steam and hot water; the secondary hot air will be used for silica gel regeneration and scrubber wastewater evaporation & crystallization in Unit 38.    Features: SO₂ cooler adopts inlet end insulation protection and floating type design, which avoids intergranular corrosion of stainless steel above 600℃, thus the working life can be extended twice as before. By combining the start-up pre-heater and waste heat recovery unit, when preheating the converter, the steam produced also can be used for sulfur melting and generating hot water, so that WEIXIAN plants don't require any external steam.

SO3 gas goes through SO3 filter with precise concentration (%), then reacts with organic raw material in the reactor. The reaction heat is removed by recycle cooling water in the reactor shell side. The exhaust gas goes to the exhaust gas treatment unit by passing the gas-liquid separator and cyclone separator; the organic acid goes to aging and stabilization unit or neutralization and dioxane stripping unit.    The flow rate of organic raw material is controlled by a mass flow meter and control valve (or VFD of gear pump); the liquid level in the gas-liquid separator is controlled by a level transmitter and VFD of discharge pump; the flow rate and density of organic acid are detected by a mass flow meter and its density is cascade controlled to adjust the raw material flow rate. The recycle cooling water inlet temperature remains constant by supplement water; cooling water flow is adjusted by the control valve, whose rate depends on the water temperature difference of the reactor in each path.     Features: WEIXIAN has more than three important improvements to increase the reliability of the reactor. Meanwhile, the size of each reactor tube, distributor, and nozzle is in high uniformity. The reactor tube is treated by high precision rolling and oxygen-free annealing process, which makes the finish degree of all tubes and each part of the tube of high uniformity. Compared to the competitors' technology, our plant has longer continuous running time and lower dioxane when producing SLES.

The LABSA (linear alkyl benzene sulphonic acid) from the separator goes to the aging vessel by first discharge pump, then stabilized in the stabilization pump with water. After cooling, the LABSA will be pumped to the finished product tanks by the second discharge pump. The liquid level of the aging vessel is controlled by a level transmitter and VFD of the second discharge pump.   Features: WEIXIAN aging vessel is a vertical and static mixing type, with no back-mixing and the aging time can be controlled, which makes it closest to the theoretical limit of aging conversion rate, and reduces the free oil content and sulfate acid content to the minimum, while correspondingly improves the active matter content close to or reach 98%. 

Before discharge, organic acid mist and SO3 will be removed from the exhaust gas by ESP, SO2 will be removed by the scrubber.   Features: WEIXIAN adopts plate-type tubes as the cathode of ESP. Compared with using steel wire as the cathode, it never needs maintenance. 

When producing SLES, the sulfate needs to be neutralized with pure water, caustic soda, H2O2, and buffer in the neutralization reactor, all materials react by high-speed mixing, then remove dioxane together with air in the stripping tower under vacuum condition, meanwhile, the cooling procedure is also done in this tower.   Features: Compared with Italy's vacuum neutralization, WEIXIAN stripping tower is a static equipment, without motor and maintenance requirement. Before going into the stripping tower, products react in the micro positive pressure reactor, so there is no acid gas corrosion happened in condensate and vacuum pump. Meanwhile this unit has a 10 times SLES recycle loop, comparing to similar technologies of other suppliers, this process makes the neutralization temperature rise less than 5℃, which helps us to get the products with lighter color, more stable pH value and lower dioxane content. This unit is able to realize ultra-low dioxane content.

Hot air firstly goes into the heat-pipe exchanger, the heat is transferred to the soft water inside, and steam of 0.4~0.6Mpa is generated. After passing through the heat-pipe exchanger, hot air is reused to pre-heat the R/O water and generate the hot water.    Features: With the waste heat recovery system, the plant doesn’t need external steam upon cold start-up. During normal operation, plants realize steam and hot water self-sufficient.

When producing SLS, the organic sulfate needs to be neutralized. In Unit 07, pure water, caustic soda, hydrogen peroxide solution, buffer, and organic sulfate are pumped to the neutralization reactor, after high-speed mixing, transported to the SLS cooler, then SLS finished product is produced.   Features: In the neutralization reactor, SLS has 10 times circulating reflux, which enables the temperature increase in neutralization reaction within 5℃. The products appearance is more transparent, pH value is more stable.

The Sulfolactone hydrolysis system consists of a boosting pump, three heat exchangers, and a hydrolyzer. After aging, α- Olefin sulfonate is pumped to the neutralization reactor. α- Olefin sulfonate, pure water, caustic soda, hydrogen peroxide solution, and buffer are pumped to the neutralization reactor, after high-speed mixing, materials were pumped to the two heat exchangers and a hydrolyzer in sequence. After hydrolyzed, the finished product AOS is produced. 

When AOS is produced, the temperatures at the top of the sulfonation reactor, aging vessel and α-olefin inlet need to be decreased to ensure product stability. A chilling water unit is required. The chilling water unit consists of a chilling water group, chilling water tank, and two circulating pumps. One circulating pump transports the water to the chilling group, decreasing the temperature to the set point, then backflow to chilling water tank; the other circulating pump transports the chilled water to the user, then backflow to chilling water tank.

Normally, in the LABSA field, there are two tanks of alkylbenzene (LAB) material tanks, two LABSA tanks and one liquid caustic soda tank, and equipped the transfer pumps for material, finished product and liquid caustic soda. If the plant is for producing multiple products, then corresponding tanks and pumps are needed. Such as AEO tanks, SLES tanks, AO tanks, AOS tanks, Fatty alcohol tanks , SLS tanks, etc.