Petrochemical Industry
Chemical technology and petrochemicals have always been primary drivers of human civilization, enabling sustainable development and improved living standards. Since the early 20th century, when crude oil and natural gas became key raw materials for chemical production, petrochemicals—as a fundamental industry—have garnered significant global attention and played an increasingly vital role in the world economy.
Over 30 years of rapid development in the modern chemical industry, THT Juyuan (now known as THT) has evolved from supplying its first plate heat exchanger to the chemical sector in 1986. Today, it has delivered over 20,000 heat exchangers to process units for clients including BP, LG, DOW, SHELL, BASF, Sinopec, and PetroChina. More than 80% of these are compact plate heat exchangers, accumulating extensive expertise.
From initially providing standalone products to progressively offering system analysis and optimization, THT understands how different equipment maximizes efficiency within process systems. This includes reducing installation/downtime, enhancing unit efficiency, lowering operational/maintenance costs, and minimizing spatial footprint. Through scientific system design, THT now delivers comprehensive solutions that surpass client expectations in safety, economy, and longevity.
Sulfuric Acid Applications
In metallurgical acid production processes, key coolers include:
Purification Acid Cooler: Cools dilute acid (5–20% concentration) with water.
Drying Acid Cooler: Handles 93–96% sulfuric acid and water.
Primary Absorption (I) & Secondary Absorption (II) Acid Coolers: Process ~98.5% concentrated sulfuric acid with water.
Primary Brine Process:
Raw salt is fed into the salt dissolving tank, where it is dissolved using weak brine from the electrolysis process, recycled water from the plant, and supplementary water to produce saturated crude brine.
Electrolysis Process:
The electrolysis process consists of three parts: secondary brine purification, electrolysis, and weak brine dechlorination.
Evaporation & Solid Caustic Soda Process:
The 32% NaOH solution from the electrolysis process undergoes triple-effect countercurrent falling-film evaporation to increase the NaOH concentration to 50%, which is then sent to the concentration unit to produce flake and granular caustic soda.
Chlorine Treatment Process:
The wet chlorine gas from the electrolysis process is first washed in a chlorine scrubber, then cooled in a chlorine cooler using chilled water. After passing through a mist separator, it enters a packed tower for countercurrent contact with sulfuric acid for initial dehydration. The chlorine gas then proceeds to a bubble cap tower for further dehydration via countercurrent contact with concentrated sulfuric acid. Finally, it passes through an acid mist eliminator before being compressed by a chlorine compressor and delivered to end users.
Waste Gas Treatment Process:
During plant startup, shutdown, or emergencies, chlorine gas is first absorbed in an absorption tower using circulating alkali liquor from the absorption tank. The tail gas is then further treated in an exhaust gas tower with additional alkali absorption, producing 10% NaClO solution for the acetylene plant.
Hydrogen Treatment Process:
The wet hydrogen gas (~85°C) from the electrolysis process enters the lower section of a hydrogen scrubber, where it is directly cooled and washed by circulating spray liquid. The entrained alkali mist and condensed steam are removed by the circulating liquid. The hydrogen is then pressurized by a hydrogen compressor and cooled in two stages before being sent out of the battery limits.
Hydrogen Chloride Synthesis & High-Purity Hydrochloric Acid Process:
Chlorine and hydrogen are combusted in a graphite synthesis furnace to produce hydrogen chloride (HCl) gas. The HCl gas is cooled in an HCl cooling water tank and an HCl cooler before being distributed—partially to the VCM plant as feedstock and partially to the high-purity HCl absorption system.
Coking:
The main production units in a coking plant include: coal preparation, coking, gas purification, and auxiliary facilities. During coking, ~75% of coal is converted into coke, while ~25% yields various chemical byproducts and coke oven gas (COG). Recovering these chemical byproducts is crucial. The COG generated in the coke oven chambers is cooled, transported, and processed in the chemical recovery plant to extract coal tar, ammonia, sulfur, benzene hydrocarbons, and other chemicals while purifying the gas. The gas purification plant consists of the condensation & blowing section, desulfurization section, ammonium sulfate section, final cooling & benzene scrubbing section, and crude benzene distillation section.
Plate-and-Frame Heat Exchangers in Coking Applications:
These exchangers are widely used in the crude benzene distillation section for lean/rich oil heat exchange, lean oil primary cooling, and lean oil secondary cooling. Their advantages include:
High heat transfer efficiency with low pressure drop.
Flexible configuration to adapt to varying process requirements.
Superior cleanability compared to spiral plate exchangers—side panels can be removed for direct steam cleaning (0.4 MPa) or mechanical washing without disassembly.
Robust temperature/pressure resistance & material compatibility. The welded structure eliminates gasket limitations, enhancing performance in high-temperature, high-pressure, and corrosive media applications compared to gasketed plate exchangers.