Model Innovation | Shuangliang Hot-Water Lithium Bromide Units Empower the Coking Industry, Breaking Through with Low-Temperature Waste Heat Combined Cooling and Heating Supply
As the "dual carbon" goals advance in depth and energy consumption limits and ultra-low emission controls in the coking industry continue to tighten, low-temperature waste heat recovery has shifted from an "optional item" to a "must-answer question." Coking production continuously releases large amounts of low-grade circulating ammonia water waste heat at around 70°C, yet under the traditional model it dissipates directly through cooling towers, wasting precious low-temperature thermal energy; meanwhile, plant summer cooling and winter heating additionally consume large quantities of steam and electricity, keeping overall energy consumption and operating costs persistently high. How can this low-temperature waste heat be activated so that a single unit handles both summer cooling and winter heating?
Leveraging over forty years of R&D and manufacturing experience in lithium bromide absorption equipment, Shuangliang Eco-Energy has deployed a hot-water-type lithium bromide combined cooling and heating unit in the Henan Tiancheng Environmental Protection Coking low-grade waste heat utilization project, driven by low-temperature waste heat from coking circulating ammonia water, achieving automatic switching between cooling and heating modes throughout the year. This pioneering new model of combined cooling and heating supply from low-temperature ammonia waste heat in coking provides a replicable, complete solution for comprehensive waste heat utilization by coal chemical and coking enterprises.
The project is configured with 1 hot-water-type lithium bromide absorption cooling/heating unit, one 3000m³/h crossflow cooling tower, a full set of PLC intelligent automatic control system, circulating pumps, valves and instruments, and titanium anti-corrosion heat exchange components. The rated cooling/heating capacity of each unit reaches 5.5 million kcal/h, capable of producing chilled water cooled from 23°C to 16°C and heating water raised from 55°C to 65°C. The unit relies on modification of the existing coking circulating ammonia water piping, with minimal civil work and short construction period, achieving "small changes, big returns."
The customized titanium anti-corrosion hot-water-type lithium bromide unit precisely adapts to 73°C coking low-temperature ammonia waste heat, with one-unit switching between cooling/heating dual modes, high-vacuum anti-crystallization + DCS remote automatic control, and stable, long-term operation across a wide water temperature range.
Waste heat drive side: 73°C coking circulating ammonia water enters the unit's generator for heat exchange, cools to 63°C and returns to the production system; the released heat serves as the unit's core driving heat source, squeezing the waste heat dry.
Cooling mode process: Circulating ammonia waste heat heats the lithium bromide solution; refrigerant water evaporates to produce low-temperature chilled water (23°C→16°C) for chemical production cooling; heat from the absorber and condenser is carried away by cooling tower circulating water, ensuring efficient and stable cooling.
Heating mode process: Switching the operating mode, recovered waste heat directly heats the heating water, raising 55°C warm water to 65°C for plant-wide heating supply; the cooling tower operates at low load, greatly reducing circulating water consumption.
Zero steam consumption, cutting boiler costs: Summer cooling and winter heating rely entirely on coking ammonia waste heat, completely eliminating steam procurement and coal costs for heating and cooling, reducing annual boiler fuel, water treatment, and manual O&M expenses by over one million yuan.
Circulating water consumption savings: Previously, ammonia water in the chemical production area was directly cooled by water; after the retrofit, waste heat recovery removes large amounts of heat, significantly reducing circulating water consumption and lowering cooling tower fan electricity costs as well as circulating water chemical and makeup water intake fees.
Extended warranty reducing costs: The main unit comes with 5 years of free maintenance, one free on-site inspection guidance per year, and free replacement of parts with quality issues during the warranty period, greatly reducing later equipment repair investment.
The project fully recovers discarded low-temperature ammonia waste heat from coking, replacing the original boiler-produced steam for cooling and heating, reducing annual coal consumption and greatly optimizing the plant's overall energy consumption indicators, meeting coking industry energy consumption limit control requirements and helping the enterprise achieve annual energy-saving assessment targets.
Simultaneous reduction of carbon emissions and pollutants: Reducing boiler coal consumption lowers annual emissions of CO₂, SO₂, NOₓ and other greenhouse gases and flue gas pollutants, aligning with the mandatory indicators for coking ultra-low emissions and green factory applications.