{"id":3095,"date":"2026-06-16T09:03:11","date_gmt":"2026-06-16T09:03:11","guid":{"rendered":"https:\/\/regenerative-thermal-oxidation.com\/?p=3095"},"modified":"2026-06-16T09:03:11","modified_gmt":"2026-06-16T09:03:11","slug":"sncrscr-combined-denitrification-and-limestone-gypsum-desulfurization-for-power-battery-lithium-carbonate-rotary-kiln-off-gas","status":"publish","type":"post","link":"https:\/\/regenerative-thermal-oxidation.com\/nl\/sollicitatie\/sncrscr-combined-denitrification-and-limestone-gypsum-desulfurization-for-power-battery-lithium-carbonate-rotary-kiln-off-gas\/","title":{"rendered":"SNCR+SCR Combined Denitrification and Limestone-Gypsum Desulfurization for Power Battery Lithium Carbonate Rotary Kiln Off-Gas"},"content":{"rendered":"

<\/p>\n

<\/p>\n
\n

Casestudie \u00b7 Industri\u00eble emissiebeheersing<\/p>\n

How a global power battery leader achieved 81.5% combined SNCR+SCR denitrification efficiency and 97.9% desulfurization from rotary kiln lithium carbonate production off-gas with SO\u2082 inlet concentrations reaching 12,000\u00a0mg\/Nm\u00b3 \u2014 deploying a dual-line SNCR+SCR+limestone-gypsum FGD+lime treatment system adapted for the extreme variability of battery-grade lithium carbonate sintering off-gas chemistry.<\/p>\n

Power Battery Rotary Kiln Off-Gas<\/span>
\nSNCR+SCR Combined Denitrification<\/span>
\nKalksteen-gips FGD<\/span>
\nLithium Carbonate Sintering<\/span>
\nUltra-Low Battery Industry Emission<\/span><\/div>\n<\/header>\n

<\/p>\n

\n
\n
97.9%<\/div>\n
Ontzwaveling<\/div>\n
Kalksteen-gips FGD<\/div>\n<\/div>\n
\n
81.5%<\/div>\n
Denitrificatie<\/div>\n
SNCR+SCR Combined<\/div>\n<\/div>\n
\n
120,000<\/div>\n
Nm\u00b3\/h<\/div>\n
Standard Flue Gas (per line)<\/div>\n<\/div>\n
\n
up to 12,000<\/div>\n
mg\/Nm\u00b3 SO\u2082 peak<\/div>\n
Most Demanding FGD Condition<\/div>\n<\/div>\n<\/div>\n

<\/p>\n

\n

01 \u2014 Achtergrondinformatie over de industrie<\/p>\n

Power Battery Lithium Carbonate Production: A Rapidly Expanding Sector With Demanding Emission Challenges<\/h2>\n

Lithium carbonate is a fundamental raw material for lithium battery manufacturing. Global demand is growing rapidly on the back of electric vehicle adoption and grid-scale energy storage expansion, with output growing from 4.1\u00a0t\/a in 2014 to 39.5\u00a0million tonnes in 2022 at a 28% compound annual growth rate, and projections pointing to 110\u00a0million tonnes capacity by 2025 and 51.79\u00a0million tonnes actual production in 2023 (year-on-year growth 31.1%). Battery-grade lithium carbonate production capacity requirements will only increase as EV markets continue to scale, driving further investment in production facilities and their associated environmental compliance infrastructure.<\/p>\n

The enterprise in this case study is one of the leading power battery companies globally, and one of the few companies with full power battery industry chain coverage. Listed on a major domestic exchange in 2015 and on the Swiss Stock Exchange in 2022 as the first power battery company in Switzerland, its main business encompasses lithium batteries for mobility applications, energy storage systems, and power distribution equipment. The \u201csolid-state battery\u201d product announced in 2024 achieves energy density of 3,500\u00a0Wh\/kg and volumetric energy density of 800\u00a0Wh\/L, with 30,000-cycle service life and theoretical range exceeding 300,000\u00a0km. The enterprise also produces approximately 100,000 distribution units annually.<\/p>\n

Lithium carbonate production uses rotary kiln sintering to convert lithium-bearing raw materials (primarily mica-derived lithium salts) into battery-grade lithium carbonate. The sintering chemistry involves high-temperature reaction of sulfate and carbonate compounds that drives the release of SO\u2082 in concentrations far exceeding those of conventional industrial boilers or power plants. As market demand for lithium carbonate grows and production facilities scale, the flue gas purification system for rotary kiln sintering becomes a critical compliance and operational bottleneck. This project deploys limestone-gypsum FGD combined with SNCR+SCR denitrification to achieve ultra-low emission targets and advance the facility\u2019s green development credentials.<\/p>\n

\"Application<\/p>\n<\/section>\n

\n

<\/p>\n

\n

02 \u2014 Vervuilingsprofiel<\/p>\n

Lithium Carbonate Rotary Kiln Off-Gas: Extreme SO\u2082 Variability as the Defining Challenge<\/h2>\n

The facility operates two rotary kiln production lines, each equipped with a cyclone dust collector + cooling unit + bag filter dust collector, processing flue gas from the sintering of lithium carbonate battery material. The kiln is fired on natural gas. The standard flue gas volume per production line is 120,000\u00a0Nm\u00b3\/h (185,897\u00a0Nm\u00b3\/h at process conditions, 150\u00b0C). After cooling, the flue gas is collected at the FGD system.<\/p>\n

The defining feature of lithium carbonate rotary kiln off-gas is the extraordinary variability of SO\u2082 concentration. During the sintering reaction cycle, lithium sulfate compounds decompose to release SO\u2082: the average SO\u2082 concentration entering the desulfurization absorber is approximately 4,645\u00a0mg\/Nm\u00b3, but peak concentrations can reach 12,000\u00a0mg\/Nm\u00b3, with baseline levels at approximately 12% oxygen-corrected concentration of around 809\u00a0mg\/Nm\u00b3 NOx. The SO\u2082 concentration swing of 10:1 between baseline and peak (from approximately 1,200\u00a0mg\/Nm\u00b3 to 12,000\u00a0mg\/Nm\u00b3) requires the FGD system to be designed for the peak condition while maintaining stable operation and gypsum quality during the baseline and mid-range periods.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nIniti\u00eble concentratie<\/th>\nDesigned Outlet<\/th>\nEU IED \/ NER-limiet<\/th>\n<\/tr>\n<\/thead>\n
NOx (as NO\u2082)<\/td>\n809 mg\/Nm\u00b3 (at 12% O\u2082, baseline ammonia content 12%)<\/td>\n\u2264150 mg\/Nm\u00b3<\/td>\nIED 2010\/75\/EU: 150\u00a0mg\/Nm\u00b3<\/td>\n<\/tr>\n
SO\u2082 (average at FGD inlet)<\/td>\n4,645 mg\/Nm\u00b3 avg; peak 12,000 mg\/Nm\u00b3<\/td>\n\u2264100 mg\/Nm\u00b3<\/td>\nNederlands Activiteitenbesluit NER<\/td>\n<\/tr>\n
Fijnstof (PM)<\/td>\n658 mg\/Nm\u00b3<\/td>\n\u226430 mg\/Nm\u00b3<\/td>\nNederlands Activiteitenbesluit NER \u22645 mg\/Nm\u00b3<\/td>\n<\/tr>\n
HCl<\/td>\n3.7 mg\/Nm\u00b3<\/td>\n\u226410 mg\/Nm\u00b3<\/td>\nIED BAT \u226410\u00a0mg\/Nm\u00b3<\/td>\n<\/tr>\n
HF<\/td>\n6.74 mg\/Nm\u00b3<\/td>\n\u22646 mg\/Nm\u00b3<\/td>\nIED BAT \u22641\u00a0mg\/Nm\u00b3<\/td>\n<\/tr>\n
Zure nevel (mist)<\/td>\n191 mg\/Nm\u00b3<\/td>\n\u226420 mg\/Nm\u00b3<\/td>\nIED-BAT<\/td>\n<\/tr>\n
Standard flue gas (per line)<\/td>\n120,000 Nm\u00b3\/h<\/td>\n\u2014<\/td>\n\u2014<\/td>\n<\/tr>\n
Process flue gas (per line)<\/td>\n185,897 Nm\u00b3\/h at 150\u00b0C<\/td>\n\u2014<\/td>\n\u2014<\/td>\n<\/tr>\n
SCR flue gas volume<\/td>\n273,846 Nm\u00b3\/h (combined 2 lines)<\/td>\n\u2014<\/td>\n\u2014<\/td>\n<\/tr>\n
Uitgangstemperatuur van de oven<\/td>\n380\u2013420\u00b0C (at SCR\/SNCR installation point)<\/td>\n\u2014<\/td>\n\u2014<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Key design challenge:<\/strong> SO\u2082 at 4,645\u00a0mg\/Nm\u00b3 average and 12,000\u00a0mg\/Nm\u00b3 peak represents an inlet concentration approximately 3\u00d7 the maximum inlet concentration of a typical coal-fired power plant FGD. The 12,000\u00a0mg\/Nm\u00b3 peak combined with the need to achieve \u2264100\u00a0mg\/Nm\u00b3 outlet (99.2% removal efficiency at peak) requires the FGD to be designed for extreme overloading above the average operating condition. This drives the need for oversized absorber towers, high liquid-to-gas ratios, and conservative calcium-to-sulfur stoichiometric ratios in the system design.<\/p>\n<\/section>\n

\n

<\/p>\n

\n

03 \u2014 Behandelingsoplossing<\/p>\n

Dual-Line Treatment Architecture: SNCR at Kiln Exit + SCR + Limestone-Gypsum FGD + Lime Desulfurization<\/h2>\n

The project covers two rotary kiln production lines. The treatment system for each line includes: cyclone pre-dedusting \u2192 gas cooling \u2192 bag filter dust removal \u2192 flue gas collection \u2192 SNCR+SCR denitrification \u2192 limestone-gypsum FGD \u2192 lime post-desulfurization. This upgrade was implemented on the existing rotary kiln production line by adding an SCR denitrification unit and a limestone-gypsum + limestone (lime) desulfurization system to achieve ultra-low emission compliance. For the second production line at the rear of the facility, a limestone-gypsum desulfurization system is simultaneously deployed to ensure SO\u2082 outlet \u2264100\u00a0mg\/Nm\u00b3, while flue gas small-hour averages achieve compliance across all parameters.<\/p>\n

SNCR Denitrification at Kiln Exit (380\u2013420\u00b0C Zone)<\/h3>\n

The SCR system installation position is selected at the multi-tube dust collector outlet of the rotary kiln exit, where temperature is maintained at 380\u2013420\u00b0C. At this temperature and with SO\u2082 content below 4,600\u00a0mg\/Nm\u00b3, a mid-temperature SCR catalyst can be used. The SCR reactor internal catalyst is designed with a 2+1 layer configuration (2 active layers + 1 spare layer). The reducing agent is ammonia water, and the front-end SNCR uses a single nozzle spray system. Front-end SNCR can guarantee the denitrification efficiency satisfies the denitrification target. For the desulfurization tower spray layers, their opening quantity is adjusted based on online monitoring values, achieving stable flue gas ultra-low emission discharge.<\/p>\n

SCR Reactor Key Parameters<\/h3>\n

Flue gas volume 273,846\u00a0m\u00b3\/h (combined 2 lines); flue gas temperature 350\u00b0C at SCR; initial NOx 809\u00a0mg\/Nm\u00b3; initial PM 658\u00a0mg\/Nm\u00b3; actual O\u2082 \u226415.2%; NOx outlet 150\u00a0mg\/Nm\u00b3; catalyst pore count 18; catalyst porosity 72.59%; catalyst layers 2+1 (1 spare layer); catalyst modules per layer 12; total catalyst volume 31.104\u00a0m\u00b3; design temperature 230\u00b0C; maximum operating temperature 350\u00b0C; minimum operating temperature 200\u00b0C; urea injection rate 111.919\u00a0kg\/h; denitrification efficiency 88%; ammonia slip \u22643\u00a0ppm; pressure drop \u2264600\u00a0Pa; soot blowing method: pulse-jet blow.<\/p>\n

\"SNCR<\/p>\n

Limestone-Gypsum FGD Absorber Tower (\u03c64.4\u00a0m, 120,000\u00a0m\u00b3\/h)<\/h3>\n

The FGD tower is the most heavily loaded piece of equipment in the system, receiving SO\u2082 at an average of 4,645\u00a0mg\/Nm\u00b3 and peak of 12,000\u00a0mg\/Nm\u00b3. To achieve \u2264100\u00a0mg\/Nm\u00b3 outlet under peak loading (99.2% removal efficiency), the tower is specified with an exceptionally high liquid-to-gas ratio of 30 and 4 spray layers. Key parameters: flue gas volume 120,000\u00a0m\u00b3\/h per tower; flue gas temperature 150\u00b0C; SO\u2082 inlet 4,645\u00a0mg\/Nm\u00b3; SO\u2082 outlet 100\u00a0mg\/Nm\u00b3; calcium-to-sulfur ratio 1.1; gas velocity <3.5\u00a0m\/s; tower internal diameter \u03c64.4\u00a0m; liquid-to-gas ratio 30; 4 spray layers; single pump flow 900\u00a0m\u00b3\/h; slurry settling time 6\u00a0h; limestone operating consumption 718\u00a0kg\/h (maximum); gypsum production 1,488\u00a0kg\/h (maximum); gypsum moisture content \u226415%; mist eliminators: 2-layer screen mist eliminator; intermediate limestone storage capacity 50\u00a0m\u00b3; 7-day autonomy.<\/p>\n

\"Design<\/p>\n

Process Flow Summary<\/h3>\n
\n
\n
Rotary Kiln
\n380\u2013420\u00b0C<\/div>\n
\u2192<\/div>\n
SNCR \u2b50
\nNH\u2083 injection
\n900\u00b0C zone<\/div>\n
\u2192<\/div>\n
Cyclone
\nPre-dedusting<\/div>\n
\u2192<\/div>\n
Cooling +
\nZakfilter<\/div>\n
\u2192<\/div>\n
SCR \u2b50
\n350\u00b0C
\n2+1 layers<\/div>\n
\u2192<\/div>\n
FGD \u2b50
\n\u03c64.4 m
\n97.9% SO\u2082<\/div>\n
\u2192<\/div>\n
Lime \u2b50
\nPost-FGD<\/div>\n
\u2192<\/div>\n
IDF-fan
\n\u2192 Stapel<\/div>\n<\/div>\n<\/div>\n

\u2b50 New or upgraded equipment in this project<\/p>\n

Key Equipment Parameters at a Glance<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Equipment<\/th>\nKey Specification<\/th>\n<\/tr>\n<\/thead>\n
Induced draft fan<\/td>\n220,000 m\u00b3\/h; 5,000 Pa; 250\u2013300\u00b0C; 335 kW per unit; 50\u00a0Hz variable speed<\/td>\n<\/tr>\n
SCR reactor<\/td>\n273,846 m\u00b3\/h; 350\u00b0C; 2+1 catalyst layers; 31.104 m\u00b3 catalyst; 88% NOx efficiency; \u22643 ppm NH\u2083 slip<\/td>\n<\/tr>\n
FGD absorber tower<\/td>\n\u03c64.4 m; 120,000 m\u00b3\/h; L\/G=30; 4 spray layers; 900 m\u00b3\/h pump; 718 kg\/h limestone; 1,488 kg\/h gypsum<\/td>\n<\/tr>\n
Gypsum production (max)<\/td>\n1,488 kg\/h; moisture content \u226415%; commercially reusable<\/td>\n<\/tr>\n
Limestone storage<\/td>\n50 m\u00b3; 7-day autonomy at maximum consumption<\/td>\n<\/tr>\n
Max system power<\/td>\n1,047.52 kW actual; 1,186.67 kW total installed<\/td>\n<\/tr>\n
Jaarlijkse elektriciteitskosten (8.000 uur)<\/td>\nApprox. 301.7 ten-thousand RMB equivalent at 0.36 RMB\/kWh<\/td>\n<\/tr>\n
Annual water cost<\/td>\nApprox. 8.8 ten-thousand RMB equivalent (5.5 t\/h; 2 RMB\/t)<\/td>\n<\/tr>\n
Annual limestone cost<\/td>\nApprox. 172.32 ten-thousand RMB equivalent (718 kg\/h; 300 RMB\/t)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n
\n

<\/p>\n

\n

04 \u2014 Kernvoordelen<\/p>\n

Why SNCR+SCR Combined Denitrification and Limestone-Gypsum FGD Is the Right Architecture for High-SO\u2082 Lithium Carbonate Kilns<\/h2>\n
    \n
  • \u2713<\/span>
    \nSNCR at the High-Temperature Kiln Zone Maximises Combined Denitrification Efficiency:<\/strong> The SNCR injection position at the rotary kiln exit (where the temperature window of 850\u20131,100\u00b0C is available) enables efficient thermal NOx decomposition without catalyst. The SNCR removes a portion of the NOx load before the gas enters the SCR reactor, reducing the total NOx load at the SCR inlet. This SNCR pre-reduction allows the downstream SCR reactor to achieve the overall 81.5% combined denitrification efficiency (from 809\u00a0mg\/Nm\u00b3 to \u2264150\u00a0mg\/Nm\u00b3) with a catalyst volume and pressure drop that would not be achievable if the SCR had to handle the full inlet NOx load alone.<\/li>\n
  • \u2713<\/span>
    \nMid-Temperature SCR at 350\u00b0C Is Viable Because the Natural Gas Kiln Contains No SO\u2082 at the SCR Inlet:<\/strong> The SCR reactor is positioned at the multi-tube dust collector outlet, where the gas temperature is approximately 350\u2013380\u00b0C and \u2014 critically \u2014 where SO\u2082 from the sintering reaction has not yet fully entered the gas stream (or has been partially removed by the upstream dust collector). Since the natural gas fuel contains no sulfur, the SO\u2082 is entirely a sintering chemistry product. The SCR placement exploits the window before the peak SO\u2082 release point to use mid-temperature catalyst without ammonium bisulfate poisoning. This contrasts with the FGD inlet (where SO\u2082 is at full 4,645\u00a0mg\/Nm\u00b3 average concentration), which would immediately destroy a standard SCR catalyst.<\/li>\n
  • \u2713<\/span>
    \nL\/G Ratio of 30 and 4 Spray Layers Achieves 97.9% FGD Removal From 4,645\u00a0mg\/Nm\u00b3 Average:<\/strong> Standard power plant FGD designs use L\/G ratios of 8\u201315 for SO\u2082 inlet concentrations of 1,000\u20133,000\u00a0mg\/Nm\u00b3. The lithium carbonate kiln FGD tower operates at L\/G=30 \u2014 more than twice the standard power plant ratio \u2014 with 4 spray layers rather than the typical 3. This combination of high liquid-to-gas ratio and additional spray contact provides the extended absorption residence time needed to achieve 97.9% desulfurization from the 4,645\u00a0mg\/Nm\u00b3 average inlet, while maintaining adequate performance margin for the 12,000\u00a0mg\/Nm\u00b3 peak condition where 99.2% removal is needed to stay within the 100\u00a0mg\/Nm\u00b3 outlet limit.<\/li>\n
  • \u2713<\/span>
    \nOnline Monitoring-Based FGD Spray Layer Control Optimises Reagent Consumption Across the Full SO\u2082 Variability Range:<\/strong> The desulfurization tower spray layer opening quantity is adjusted based on online SO\u2082 monitoring data from both the FGD inlet and outlet. During baseline SO\u2082 periods (when inlet is at the lower range of the 4,645\u00a0mg\/Nm\u00b3 average), fewer spray layers are activated, reducing pump energy consumption and limestone slurry circulation rate. During peak SO\u2082 events, all 4 spray layers are activated simultaneously. This dynamic spray layer management significantly reduces the annual energy and reagent cost compared with running all 4 layers continuously at maximum flow rate regardless of actual SO\u2082 load.<\/li>\n
  • \u2713<\/span>
    \nGypsum By-Product at 1,488\u00a0kg\/h (Maximum) Has Direct Commercial Value:<\/strong> The exceptionally high gypsum production rate (1,488\u00a0kg\/h maximum, reflecting the 4,645\u00a0mg\/Nm\u00b3 average SO\u2082 inlet concentration) makes this FGD system a significant gypsum producer. At \u226415% moisture content, the gypsum meets the quality specification for construction material reuse (wallboard substrate, cement additive) if chloride content is within the EN 13279-1 specification limit. This positions the FGD system as a value-generating by-product process rather than simply a compliance cost centre, partially offsetting the 718\u00a0kg\/h limestone reagent cost through gypsum sales revenue.<\/li>\n
  • \u2713<\/span>
    \nLimestone-Gypsum FGD Design Principles Applied: Seven Advantages for Lithium Carbonate Applications:<\/strong> The limestone-gypsum process was selected for this application for the same seven principles validated in power plant applications: (1) low energy consumption and operating cost; (2) gypsum by-product manageable without secondary pollution; (3) small footprint and rational flow design; (4) computer simulation-optimized design; (5) optimized gas velocity for uniform absorption; (6) limestone raw material is widely sourced and low-cost; (7) tower internals using counter-current spraying and mist eliminators to reduce tower wall deposition. These principles are directly applicable to lithium carbonate rotary kiln FGD, and the operational experience from thousands of power plant FGD installations provides a strong knowledge base for system design and troubleshooting.<\/li>\n<\/ul>\n<\/section>\n
    \n

    <\/p>\n

    \n

    05 \u2014 Operationele resultaten<\/p>\n

    Verified Compliance Data and Annual Cost Summary<\/h2>\n
    \n
    \n
    \u2264150<\/div>\n
    mg\/Nm\u00b3 NOx outlet<\/div>\n
    81.5% SNCR+SCR<\/div>\n<\/div>\n
    \n
    \u2264100<\/div>\n
    mg\/Nm\u00b3 SO\u2082 outlet<\/div>\n
    97.9% FGD<\/div>\n<\/div>\n
    \n
    \u226430<\/div>\n
    mg\/Nm\u00b3 PM outlet<\/div>\n
    Design target met<\/div>\n<\/div>\n
    \n
    1.047 kW<\/div>\n
    werkelijk loopvermogen<\/div>\n
    (max installed 1,186 kW)<\/div>\n<\/div>\n<\/div>\n

    \"Operational<\/p>\n

    Maximum system running power: 1,047.52\u00a0kW (actual). At 8,000 annual hours and 0.36\u00a0RMB\/kWh equivalent, annual electricity cost is approximately 301.7\u00a0ten-thousand RMB equivalent. Annual water cost: approximately 8.8\u00a0ten-thousand RMB equivalent (5.5\u00a0t\/h, 2\u00a0RMB\/t). Annual limestone cost: approximately 172.32\u00a0ten-thousand RMB equivalent (718\u00a0kg\/h at 300\u00a0RMB\/t). Gypsum by-product revenue at 1,488\u00a0kg\/h maximum production partially offsets these reagent costs.<\/p>\n<\/section>\n

    \n

    <\/p>\n

    \n

    06 \u2014 Waarschuwingen bij de implementatie<\/p>\n

    Critical Engineering Considerations for Lithium Carbonate Rotary Kiln Off-Gas Treatment<\/h2>\n
      \n
    • \u26a0\ufe0f<\/span>
      \nUpstream SO\u2082 concentration fluctuations (from production line processing conditions) cause FGD system overload and impact desulfurization efficiency \u2014 the primary risk:<\/strong> The primary documented operational risk is that upstream process fluctuations cause SO\u2082 concentration swings that drive the FGD system into overloaded operation, causing system discharge instability. With SO\u2082 peak concentrations at 12,000\u00a0mg\/Nm\u00b3 and average at 4,645\u00a0mg\/Nm\u00b3, the FGD is already sized for extreme overloading above a typical power plant condition. Any additional SO\u2082 spike above the 12,000\u00a0mg\/Nm\u00b3 design peak can push the system into genuine non-compliance. Implement SO\u2082 monitoring at both the FGD inlet (before absorption) and outlet (after absorption) with real-time feedback to the spray layer control, and establish a protocol for advance notification from the production team before any operating changes that affect sintering chemistry and SO\u2082 release rate.<\/li>\n
    • \u26a0\ufe0f<\/span>
      \nSNCR nozzle positioning in the rotary kiln requires careful attention \u2014 the kiln wall is mainly caused by high-temperature evaporation, and the flue gas contains high dust that easily causes catalyst blockage:<\/strong> The project experience explicitly identifies two SNCR-specific risks: (1) the injection pipeline in the rotating section of the rotary kiln must be carefully handled \u2014 kiln wall adhesion is primarily caused by high-temperature evaporation processes, requiring nozzle materials and installation methods that can withstand thermal cycling; (2) since the flue gas at the SNCR injection point contains high dust loading, the SCR catalyst downstream is susceptible to blockage by particulates. The SCR soot blowing system (pulse-jet blow) must be operated at the calibrated frequency from commissioning day, and the first catalyst inspection at 6 months should include a comprehensive pressure drop measurement across all catalyst layers to verify that blockage rate is within acceptable bounds.<\/li>\n
    • \u26a0\ufe0f<\/span>
      \nSNCR denitrification temperature is critical \u2014 only within the appropriate temperature range can ideal denitrification efficiency be achieved:<\/strong> The SNCR injection point must maintain the gas temperature in the 850\u20131,100\u00b0C window for effective thermal NOx decomposition. Below 850\u00b0C, the NOx-NH\u2083 thermal reaction is too slow for effective reduction; above 1,100\u00b0C, the ammonia oxidises to form additional NOx rather than reducing it. The SNCR injection point temperature must be continuously monitored, and the ammonia water flow rate must be adjusted in real time to compensate for temperature variations across the injection zone. A non-uniform temperature distribution across the kiln cross-section (common in rotary kilns with variable feed rates) can create simultaneously over-temperature zones and under-temperature zones, reducing effective SNCR removal efficiency.<\/li>\n
    • \u26a0\ufe0f<\/span>
      \nThe extreme FGD limestone consumption rate (718\u00a0kg\/h maximum) requires reliable supply chain management and adequate on-site storage:<\/strong> At 718\u00a0kg\/h maximum limestone consumption and 50\u00a0m\u00b3 on-site storage (7-day autonomy), the limestone supply chain must deliver a reliable weekly supply. Any supply interruption that depletes the limestone storage below the minimum operating level will force reduction in SO\u2082 treatment capacity, creating a compliance risk within hours. Implement supply contract provisions requiring guaranteed delivery frequency, maintain a minimum inventory trigger level (e.g. 3-day remaining supply) that triggers an automatic purchase order, and document the contingency procedure for temporary FGD rate reduction during supply interruption events.<\/li>\n
    • \u26a0\ufe0f<\/span>
      \nFGD slurry pH and calcium sulfite oxidation must be actively managed to prevent scaling and maintain gypsum quality:<\/strong> At the high SO\u2082 inlet concentrations of this application, the FGD slurry loop accumulates sulfite and sulfate at rates far above power plant FGD practice. The pH management windows are critical: when primary scrubber circulation loop pH falls below 4.5, add slurry and maintain pH at 4.5\u20135.5; when secondary scrubber circulation loop pH falls below 5.5, add slurry and maintain at 5.5\u20136.5. The oxidation fan must run continuously to ensure adequate air supply for calcium sulfite oxidation to gypsum \u2014 incomplete oxidation produces calcium sulfite scaling in the absorber rather than the filterable gypsum crystals that can be dewatered to \u226415% moisture.<\/li>\n
    • \u26a0\ufe0f<\/span>
      \nFlue gas entering the desulfurization system with high SO\u2082 concentration may cause FGD overloaded operation \u2014 adopt high-efficiency calcium-based desulfurization reagent and improve desulfurization efficiency:<\/strong> Based on the documented experience summary, the critical point of this process is: when upstream SO\u2082 peaks at 12,000\u00a0mg\/Nm\u00b3, the FGD system can be near its absorption capacity limit even with L\/G=30 and 4 spray layers. At this point, the limestone slurry must be at optimal pH with fully activated oxidation, and all 4 spray layers must be running at maximum flow. If the limestone quality degrades (lower CaCO\u2083 purity), or if any spray nozzle blockage reduces effective coverage, or if the slurry pH has drifted low, the system will fail to meet the \u2264100\u00a0mg\/Nm\u00b3 outlet during the peak event. Regular (weekly) spray nozzle inspection is required to ensure full coverage is maintained at all times.<\/li>\n<\/ul>\n<\/section>\n
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      07 \u2014 Belangrijkste punten uit de techniek<\/p>\n

      Four Lessons from This Power Battery Lithium Carbonate Kiln Off-Gas Project<\/h2>\n
        \n
      • 1<\/span>
        \nSNCR+SCR combination is essential when the NOx inlet is above 600\u00a0mg\/Nm\u00b3 and the target outlet is \u2264150\u00a0mg\/Nm\u00b3 \u2014 neither technology alone can deliver the required 81.5% removal efficiency at this FGD inlet condition.<\/strong> SNCR alone achieves 30\u201350% NOx removal but with limited selectivity and sensitivity to temperature variation. SCR alone at 273,846\u00a0m\u00b3\/h would require an impractically large catalyst volume to achieve 81.5% removal from 809\u00a0mg\/Nm\u00b3. The SNCR pre-reduction reduces the SCR inlet NOx to a manageable level while the SCR provides the precise, high-efficiency reduction needed to meet the \u2264150\u00a0mg\/Nm\u00b3 limit reliably. The combined SNCR+SCR architecture is the standard recommendation for any application where inlet NOx exceeds 600\u00a0mg\/Nm\u00b3 and outlet must be below 200\u00a0mg\/Nm\u00b3.<\/li>\n
      • 2<\/span>
        \nDesign the FGD for the peak SO\u2082 condition, not the average \u2014 for a 10:1 variability ratio, the difference in system sizing is substantial.<\/strong> The average SO\u2082 of 4,645\u00a0mg\/Nm\u00b3 and the peak of 12,000\u00a0mg\/Nm\u00b3 require the same target outlet of \u2264100\u00a0mg\/Nm\u00b3. At average inlet, removal efficiency is 97.8%; at peak inlet, 99.2% is required. Designing for average conditions (97.8% removal) and scaling the system accordingly would result in compliance exceedances during every peak SO\u2082 event. The FGD must be sized for 99.2% removal efficiency under the 12,000\u00a0mg\/Nm\u00b3 peak condition, which drives the L\/G=30 specification and 4-spray-layer design. The compliance margin during average conditions (outlet well below 100\u00a0mg\/Nm\u00b3) is the natural result of a correctly peak-sized system.<\/li>\n
      • 3<\/span>
        \nOnline monitoring-based dynamic spray layer control converts variable SO\u2082 load from an operational problem into an operational advantage.<\/strong> The spray layer activation control based on online SO\u2082 monitoring turns the 10:1 SO\u2082 variability from a system stress factor into an energy and reagent optimisation opportunity. During baseline SO\u2082 periods, 1\u20132 spray layers are sufficient; during peak periods, all 4 are activated. This dynamic management reduces pump electricity consumption and limestone slurry circulation during low-SO\u2082 periods by 50\u201375% versus always running all 4 layers, delivering significant annual OPEX savings while maintaining full compliance across all SO\u2082 conditions.<\/li>\n
      • 4<\/span>
        \nGypsum production at 1,488\u00a0kg\/h from high-SO\u2082 lithium carbonate FGD is large enough to require an active gypsum marketing strategy, not just a disposal plan.<\/strong> At maximum production rate, this FGD generates approximately 35.7\u00a0tonnes of gypsum per 24-hour operating day. This is a commercially significant volume that warrants establishing a supply agreement with a construction gypsum processing facility before commissioning, rather than treating gypsum disposal as an afterthought. If the gypsum quality (chloride content, moisture, heavy metal content) meets the applicable standards for construction material reuse, the revenue from gypsum sales can meaningfully offset the 718\u00a0kg\/h limestone reagent cost.<\/li>\n<\/ul>\n<\/section>\n
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        08 \u2014 Veelgestelde vragen<\/p>\n

        Power Battery Lithium Carbonate Rotary Kiln Off-Gas Treatment: Ten Questions Answered<\/h2>\n

        Questions from environmental permit managers, process engineers, and sustainability teams at power battery material production facilities planning SCR denitrification and high-SO\u2082 FGD upgrades under EU IED \/ Dutch Activities Decree requirements.<\/p>\n

        \nQ1. Why is SNCR used in combination with SCR rather than using SCR alone for the denitrification?<\/summary>\n
        At 809\u00a0mg\/Nm\u00b3 NOx inlet and a target of \u2264150\u00a0mg\/Nm\u00b3 outlet (81.5% total removal efficiency), using SCR alone would require a catalyst volume far larger than is practical for this application. The combined SNCR+SCR approach splits the removal task: SNCR handles the initial 40\u201350% reduction in the high-temperature kiln zone (380\u2013420\u00b0C), where no catalyst is needed and the thermal decomposition mechanism is efficient. SCR then handles the precision final-stage reduction from the SNCR outlet to below 150\u00a0mg\/Nm\u00b3. The SNCR pre-reduction halves the NOx load at the SCR inlet, reducing the required catalyst volume by approximately 40% compared with SCR alone, while also enabling a smaller SCR pressure drop, lower SCR reactor capital cost, and lower catalyst change-out frequency. The tradeoff is the additional complexity of the SNCR nozzle installation in the rotating kiln zone.<\/div>\n<\/details>\n
        \nQ2. How does the FGD system maintain compliance during the 12,000\u00a0mg\/Nm\u00b3 peak SO\u2082 events?<\/summary>\n
        During peak SO\u2082 events at 12,000\u00a0mg\/Nm\u00b3, the required removal efficiency to achieve \u2264100\u00a0mg\/Nm\u00b3 outlet is 99.2%. The FGD system achieves this through: (1) all 4 spray layers activated simultaneously at maximum pump flow rate; (2) the SO\u2082 online monitoring system detects the rising inlet concentration and activates additional spray layers before the peak reaches the absorber; (3) the limestone slurry pH is pre-adjusted to the higher end of the absorption optimum (pH 5\u20135.5 primary tower, pH 5.5\u20136.5 secondary tower) before the peak event; (4) the high L\/G ratio of 30 provides sufficient liquid contact surface area for the required absorption residence time even at peak SO\u2082 loading. The combination of these measures delivers the 99.2% removal efficiency needed during peaks, while the same system at average SO\u2082 loading delivers >97.8% removal with all 4 spray layers active.<\/div>\n<\/details>\n
        \nQ3. What EU IED and Dutch regulatory framework applies to power battery lithium carbonate production facilities?<\/summary>\n
        Lithium carbonate production facilities in the Netherlands fall under the EU Industrial Emissions Directive (IED 2010\/75\/EU) in the inorganic chemical manufacturing sector. The applicable BAT conclusions set emission limit values for SO\u2082, NOx, PM, HCl, HF, and heavy metals. Dutch environmental permits are issued under the Activities Decree (Activiteitenbesluit milieubeheer) and the Omgevingswet by the provincial Omgevingsdienst. For high-SO\u2082 lithium carbonate sintering kilns, the Dutch NER (Netherlands Emission Guidelines, Nederlandse emissierichtlijn lucht) provides additional sector-specific guidance. CEMS must be certified to EN 14181 QAL1\/QAL2\/AST standards and connected to the reporting system. Annual compliance reporting under E-PRTR Regulation (EC) 166\/2006 is required above reporting thresholds. Given the relatively new nature of large-scale lithium carbonate production in the EU context, early engagement with the Omgevingsdienst before the permit application is recommended to establish agreed emission limit values and monitoring requirements.<\/div>\n<\/details>\n
        \nQ4. Why is L\/G=30 specified for this FGD when power plant FGD typically uses L\/G=8\u201315?<\/summary>\n
        The liquid-to-gas ratio (L\/G) in FGD scrubbers determines the contact surface area between the liquid limestone slurry droplets and the SO\u2082-containing gas. For power plant FGD at 1,000\u20133,000\u00a0mg\/Nm\u00b3 SO\u2082 inlet and 95\u201398% removal requirement, L\/G=8\u201315 provides sufficient contact area. At 4,645\u00a0mg\/Nm\u00b3 average and 12,000\u00a0mg\/Nm\u00b3 peak SO\u2082 inlet with 97.8\u201399.2% removal requirement, the absorption driving force calculation requires significantly more liquid-gas contact area per unit volume of gas treated. L\/G=30 provides approximately 2\u00d7 the liquid-gas contact area of a standard power plant FGD, compensating for the higher SO\u2082 partial pressure at the gas phase (which reduces the absorption rate per unit contact area) and the higher removal efficiency requirement. The 4-spray-layer design provides the tower height and contact zone needed to accommodate the L\/G=30 flow without excessive pressure drop.<\/div>\n<\/details>\n
        \nQ5. What annual operating costs should be budgeted for this dual-line treatment system?<\/summary>\n
        The main annual operating cost categories are: (1) Electricity: 1,047.52\u00a0kW actual running power, approximately 301.7\u00a0ten-thousand RMB equivalent per year at 8,000\u00a0h and 0.36\u00a0RMB\/kWh; (2) Water: approximately 8.8\u00a0ten-thousand RMB equivalent (5.5\u00a0t\/h, 2\u00a0RMB\/t, 8,000\u00a0h); (3) Limestone: approximately 172.32\u00a0ten-thousand RMB equivalent (718\u00a0kg\/h, 300\u00a0RMB\/t, 8,000\u00a0h) \u2014 this is the largest reagent cost item by far; (4) SCR catalyst change-out: every 24,000 operating hours (approximately 3 years at 8,000\u00a0h\/year), the 2-active-layer catalyst must be replaced using the spare 3rd layer as a buffer. Catalyst cost and change-out labour should be provisioned in the 3-year maintenance budget; (5) Gypsum by-product sales credit: at 1,488\u00a0kg\/h maximum production at commercial gypsum prices, the gypsum sales can offset a meaningful fraction of the limestone reagent cost.<\/div>\n<\/details>\n
        \nQ6. How is ammonia slip controlled in the SNCR+SCR combined system?<\/summary>\n
        Ammonia slip in the combined SNCR+SCR system has two potential sources: the SNCR stage (where excess ammonia injection can result in unreacted ammonia entering the SCR inlet) and the SCR stage (where insufficient catalyst activity or over-injection can result in ammonia breakthrough to the stack). The system controls are: (1) SNCR ammonia injection rate is modulated by the measured NOx concentration at the SCR inlet \u2014 if SCR inlet NOx is lower than the target set-point for the SNCR pre-reduction, SNCR injection rate is reduced to prevent excess ammonia supply; (2) SCR outlet ammonia slip is continuously monitored with a set-point alarm at 2\u00a0ppm and automatic injection rate reduction triggered at 3\u00a0ppm (design maximum 3\u00a0ppm); (3) periodic catalyst activity testing confirms that the catalyst is maintaining design-level NOx selectivity, providing early warning of catalyst deactivation that would cause increased ammonia slip at normal injection rates.<\/div>\n<\/details>\n
        \nQ7. What happens if the FGD limestone supply is interrupted for more than 24 hours?<\/summary>\n
        The 50\u00a0m\u00b3 limestone storage (7-day autonomy at maximum consumption) provides adequate buffer for typical supply disruptions. If supply is interrupted and storage begins to deplete below the minimum operating level, the contingency procedure should: (1) Reduce kiln production rate to reduce the flue gas volume and SO\u2082 flux entering the FGD, extending the time the available limestone can maintain compliance; (2) Switch from limestone-gypsum FGD to lime (quicklime or slaked lime) as a substitute absorber reagent if lime supply is available and the absorber tower can be switched over operationally; (3) Notify the competent authority (Omgevingsdienst) immediately if it becomes necessary to operate the kiln in a manner that may cause emission limit exceedances; (4) Document the event and corrective actions in the environmental register as required under the operating permit. Supply contracts should include guaranteed delivery frequency commitments and emergency supply provisions.<\/div>\n<\/details>\n
        \nQ8. How is the FGD gypsum quality managed to ensure it meets construction material reuse standards?<\/summary>\n
        FGD gypsum quality for construction material reuse is governed by EN 13279-1 (gypsum binders and gypsum-based plasters). The key quality parameters are: moisture content (\u226415% for this installation); CaSO\u2084\u00b72H\u2082O purity (typically \u226590% for construction grade); chloride content (should be \u22640.01% Cl by mass for wallboard applications, affected by HCl carry-over from the kiln off-gas); heavy metal content (characterised against the applicable limit values for the intended reuse application). For lithium carbonate kiln gypsum specifically, the lithium content in the gypsum must also be measured \u2014 residual lithium compounds from the sintering off-gas may precipitate in the FGD slurry loop, potentially affecting gypsum purity. Monthly gypsum quality testing is recommended, with the test scope matched to the specific reuse application\u2019s quality specification requirements.<\/div>\n<\/details>\n
        \nQ9. What CEMS monitoring is required for a lithium carbonate production facility under Dutch environmental permit?<\/summary>\n
        Under Dutch environmental permit conditions for IED installations in the inorganic chemical sector, CEMS at the stack must typically cover: SO\u2082, NOx, PM, CO, O\u2082, temperature, flow rate, and moisture content as continuous parameters. For lithium carbonate specifically, HF may be required as a continuous or periodic monitoring parameter given its presence at 6.74\u00a0mg\/Nm\u00b3 in the inlet. Ammonia slip from the SNCR+SCR system should be continuously monitored as a process control parameter, and periodic reporting to the authority on ammonia concentration may be required as a secondary pollutant. All CEMS must be certified to EN 14181 QAL1\/QAL2\/AST. Annual compliance data must be submitted to the Omgevingsdienst and reported to the E-PRTR system above reporting thresholds.<\/div>\n<\/details>\n
        \nQ10. Are there reference installations for high-SO\u2082 lithium carbonate kiln SNCR+SCR+FGD systems available for site visits?<\/summary>\n
        Yes. The SNCR+SCR combined denitrification and limestone-gypsum FGD desulfurization technology described in this case study has been deployed at power battery lithium carbonate production facilities achieving ultra-low emission compliance under demanding high-SO\u2082 inlet conditions. Reference site visits can be arranged for qualified prospective clients, including access to verified CEMS compliance data, gypsum quality testing records, and operational documentation covering the full SO\u2082 variability range. Please use the contact link below to request reference documentation or to arrange a site visit at a comparable lithium carbonate kiln off-gas treatment installation.<\/div>\n<\/details>\n<\/section>\n
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        \n

        Ready to Achieve Ultra-Low Emission Compliance for Your Battery Materials Kiln?<\/p>\n

        Ontdek het complete assortiment industri\u00eble emissiebeheersingsoplossingen.<\/h2>\n

        From SNCR+SCR denitrification and high-SO\u2082 limestone-gypsum FGD for lithium carbonate rotary kilns to Regeneratieve thermische oxidatiesystemen voor de reductie van VOC's in de industrie.<\/a>, our engineering team delivers EU IED\u2013compliant solutions for the most demanding new energy battery materials emission control requirements.<\/p>\n

        Vraag een technisch adviesgesprek aan \u2192<\/a>
        \n        Ontdek alle emissiebeheersingstechnologie\u00ebn<\/a><\/div>\n<\/section>\n

        <\/p>\n